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VERITAS
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ה עוית הויד

UNIV
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Fig. 28.-First wash of the Diamond-yielding Soil in Brazil.

DIAMONDS
AND
PRECIOUS STONES,
A POPULAR ACCOUNT OF GEMS.
CONTAINING
THEIR HISTORY, THEIR DISTINCTIVE PROPERTIES, ANd a
DESCRIPTION OF THE MOST FAMOUS GEMS';
GEM CUTTING AND ENGRAVING, AND THE ARTIFICIAL PRODUCTION
OF REAL AND OF COUNTERFEIT GEMS.
TRANSLATED FROM the french OF
LOUIS DIEULAFAIT,
Professor of Physics, Doctor of Sciences.
BY FANCHON SANFORD.
ILLUSTRATED BY 126 ENGRAVINGS ON WOOD.
NEW YORK:
SCRIBNER, ARMSTRONG, AND COMPANY.
1876.

Storage/
Scienfr
Ubrary
TS
752
D573
1876
フ
​Entered, according to Act of Congress, in the year 1878, by
SCRIBNER, ARMSTRONG, AND COMPANY.
In the Office of the Librarian of Congress, at Washington.
}

RIVERSIDE, CAMBRIDGE:
STEREOTYPED AND PRINTED BY
H. O. HOUGHTON AND COMPANY.


Suine Lib
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PREFACE.
{
It would be easy for any one who had sufficiently pre-
pared himself by previous study to write a purely scientific
work on the subject of precious stones; but this is not
the intention of the present writer, who aims at interesting
a wider class of readers than a work of the kind indicated
would reach.
In addition to the strictly scientific information to be
given regarding precious stones, there are connected with
them a great many facts not less interesting, and equally
important for the public to know. To these we have
devoted several sections of the following work.
In our times precious stones are used almost ex-
clusively for the purpose of ornament, but in former
times the case was very different. By reference to the
authors of antiquity, as well as to those of the middle
ages and the Renaissance, we have shown the important
part that they then played, and what ideas prevailed
regarding them.
From the thousands of fables and superstitions of
which precious stones have been the subject, we have
selected a certain number. In doing so we have dis-
regarded those calculated only to interest the curious,

iv
PREFACE.
and have chosen such as were likely to instruct and
enlighten.
In Parts iv. and v. it was necessary to introduce some
of the elements of crystallography, without which those
two important chapters would have lost a great part of
their value. We have treated the subject, however, as
briefly as possible, but, at the same time, in a strictly
scientific manner. To attempt to popularize science, by
stripping it, as is so often done, of that which constitutes
its very essence, is not to popularize, but to disfigure and
travesty it.
The part devoted to counterfeit precious stones will
not be one of the least useful. The facts which it con-
tains will carry their own teaching with them, and of
this the purchasers of precious stones will know how
to avail themselves.
In another part the methods are explained, by means
of which modern savants have succeeded in producing
the majority of the precious stones. These methods,
and the remarkable results obtained by the employment
of them, have hitherto remained locked up in collections
of scientific papers, or in special treatises. We are glad
to have had the opportunity of first making them known
to the public at large.
The illustrations interspersed through the book all re-
produce as accurately as possible by engraving the ob-
jects they profess to represent, and none of them are
fancy sketches. The utmost care has been bestowed on
this department; for, if the engraver's art is one of the
+


PREFACE.
V
most powerful means of spreading knowledge, it can only
be so by the exact reproduction of nature.
Lastly, we have constantly endeavoured to arrange
facts according to their natural relations, so as, by the
mere exposition, to exhibit, in a succinct form, a notable
stage in the development of the human mind, both from
an intellectual and a scientific point of view.
LOUIS DIEULAFAIT.
•

#
CONTENTS.
PART I.
PRECIOUS STONES: their origin; geological position;
physical characteristics; optical and electrical proper-
ties; external characteristics; susceptibility to the
action of light and heat, .
PART II.
Historical Survey of Precious Stones.—Ideas entertained
by the ancients, and in the middle ages, concerning
the nature and properties of precious stones.—Their
classification based upon the analysis of modern
chemistry,.
PAGE
I
31
The Diamond,
PART III.
PART IV.
Sapphire.-Ruby.—Balas Ruby.—Spinel Ruby.—Topaz.
-Emerald. Beryl. — Aquamarine. — Cymophane.—
Turquoise,.
PART V.
Quartz.-Occidental Topaz.-Smoky Topaz, or Alençon
Diamond.—Water Sapphire.—False Emerald.—Bohe-
mian or Brazilian Ruby.--Hyacinth of Compostella.—
Iris. — Aventurine. — Opal. — Hydrophane. — Agate.—
Chalcedony.-Chrysoprase.-Cacholong.-Heliotrope.
-
· 53
110

viii
CONTENTS.
-Onyx.-Sard. -Sardonyx.-Sardoine.-Sardagate.
-Jasper. - Zircon.-Garnets.-Peridote.-Olivine.—
Jade.—Tourmaline. — Lapis-lazuli. — Malachite.-He-
matite,
-
PART VI.
Pearl-Coral-Amber.-Jet, .
PART VII.
PAGE
. 146
. 186
Artificial Production of the Diamond.-Boron Diamond
-Cagniard de Latour-Gannal-MM. Despretz and
de Chancourtois,
208
PART VIII.
Artificial Production of Real Precious Stones.-Results
obtained. Becquerel. - Ebelman. — Gaudin.— Henri
Sainte-Claire Deville.-De Sénarmont.-Daubrée.—
Durocher.-Sainte-Claire Deville and Caron, &c., .
False Precious Stones,
PART IX.
PART X.
Cutting.-Setting.-Engraving of Precious Stones,
•
TABLE OF GENERAL CHARACTERISTICS OF PRECIOUS
STONES,
222
· 233
252
290

LIST OF THE ILLUSTRATIONS.
FIG.
1. Igneous Rocks-The Volcano of Jorullo in Mexico,
•
2. Igneous Rocks-Horizontal Columnar Basalt at St.
Helena,
3. Structure of Sedimentary Rocks,
4. Trilobites,
5. Lyell's Cephalaspis,
6. Calamite,
6a. Lepidodendron,
7. Fossil Dragon-fly,
8. Turrilites catenata,
9. Terebratula,
10. Mammillary Ammonite,
II. Cerithium thiara,
12. Gigantic Cerithium,
13. Cancellaria cancellata,
14. The Great Palæotherium,
15. The Common Anoplotherium,
PAGE
3
78
8
9
9
9
9
IO
II
II
II
12
12
12
13
14
20
21
16. Course of a luminous ray in a homogeneous medium,
17. Double refraction of Iceland spar,
18. Aspect of a candle seen through a doubly refractive
crystal,
19. Egyptian Scarabæus cut in hard stone,
23
•
32
20, 21. Egyptian figures carved in hard stone,
34
22. Cornelian engraved: Egyptian,
35
23. Egyptian Ring of Cornelian,
35
24, 25. Egyptian Rings and Tablets engraved on both sides,
26. View in a Diamond District of Brazil,
36
59
27. Size of a Diamond hidden by a slave in the corner of
·
his eye,
61
28. First wash of the Diamond-yielding Soil in Brazil,
63

X
LIST OF THE ILLUSTRATIONS.
FIG.
29. Dimensions of a Brilliant of 10 carats,
30. Maillard's Experiment,
PAGE
74
78
31. Combustion of the Diamond by Lavoisier,
32, 33. Combustion of the Diamond in Oxygen,
34. Diamond of the Rajah of Mattan, .
35. The Nizam Diainond,
36. The Regent or Pitt Diamond,
37. Empress Eugénie Diamond,
38. The Sancy Diamond,
•
39. Star of the South Diamond before and after cutting,
40. The Koh-i-noor Diamond before re-cutting,
41. The Koh-i-noor Diamond after being re-cut,
42. The Pigott Diamond, .
43. The Nassac Diamond,
•
81
82, 83
85
86
87
89
90
93
95
98
99
99
100
44. The Orlow Diamond,
45. Surface of Rose-cut Diamonds compared with their
Weight,
46. The Shah Diamond,
47. The Polar Star Diamond,
48. The Grand-duke of Tuscany Diamond,
49. The Pasha of Egypt Diamond,
50. The Blue Diamond of Mr. Hope,
51. Surfaces of Brilliants compared with their Weight,
52. Primitive Form of Corundum,
•
53. Most common Form of the Corundum,
54. King of Persia's Ruby,
55. Ruby of the King of Visapur,
ΙΟΙ
103
104
104
105
106
107
113
113
119
120
120
125
129
129
129
130
130
132
134
134
..
139
148
148
56. Indian Ruby, from Tavernier,
57. View of the Mountain of Expilly, Central France,
58. Type of Crystal of Topaz,
59. Saxon Topaz,
60. Brazilian Topaz,
61. Siberian Topaz,
62. Topaz of the Grand Mogul,
63. Amethyst engraved-Antonia, wife of Drusus,
64. Fundamental Form of Emerald Crystals,
65. Very common Form of Emerald Crystals,
66. Aquamarine engraved-Julia, daughter of Titus,
67. Primitive Form of Quartz,
•
68. Most ordinary Form of Quartz Crystals, .
1

LIST OF THE ILLUSTRATIONS.
xi
FIG.
69, 70. Modified Crystals of Quartz,
71. Dodecahedral Quartz,
72. The Great Geyser (Opals and Chalcedonies),
73. Opal of D'Augny, .
74. Agate engraved-Alexander the Great,
75. Chalcedony-Cameo of Hyllus,
•
76. Cornelian engraved-Seal of Michael Angelo, .
77. The Zircon, .
78. Modified Zircon,
79. Zircon from the Cabinet of M. Drée,
80. Garnet, Rhomboidal type,
81. Garnet, Trapezohedral type,
82. Common Form of Tourmaline,
83. Sardonyx engraved―Marriage of Cupid and Psyche.
84. Arrangement of Layers of Pearl,
85. Arrangement of Layers of Mother-of-pearl, .
•
86. Polypes of Coral in different degrees of development,
87. Lizard imprisoned in a fragment of Amber,
PAGE
149
150
158
161
169
•
170
170
172
172
172
174
174
181
•
187
190
190
200
205
215
88. Gannal's arrangement for the Production of the Diamond,
89. M. Despretz's arrangement for the Production of the
Diamond,
217
90. Voltaic Apparatus of M. Becquerel for the Production of
Crystals,
226
91. Egyptian Bracelet in Ceramic Paste, with coloured orna-
mentation,
239
92. Egyptian Vase of Blue Glass, with white and yellow
ornaments,
•
240
93. Egyptian Moulding in Ceramic Paste,
241
94. Egyptian Ring, with a Bezel of Ceramic Paste,
95. Egyptian Ring of Gold, with inlaid work of Enamel,
241
242
96. Egyptian Moulding in Ceramic Paste,
243
•
105.
Do.
97. View of Coster's Diamond Works at Amsterdam,
98. Cubic System,
99. Regular Octahedron,
•
100, 101. Common Forms of the Diamond,
102. Flat Diamond of the Grand Mogul,
103. Natural Octahedral Diamond,
104. Transitionary Form of the Diamond in arriving at the
Form of the Brilliant,
do.
255
257
257
257
·
258
·
259
•
259
259

xii
LIST OF THE ILLUSTRATIONS.
FIG.
106. Brilliant, seen sidewise,
PAGE
260
107. Brilliant, seen from above,
108. Semi-brilliant,
109. Holland Rose,
110. Pendeloque of Tavernier,
III. The Star invented by Caire,
260
261
262
•
263
264
112. Room in which the Diamond-splitters work in Coster's
Establishment, Amsterdam,
113. Details of a Compartment of the Splitter's Workroom,
114. The Splitter,
115. Table of the Splitter,
116. The Cutter,
•
117. Diamond-cutter's Table,
118. General View of the Polishing-room,
265
•
267
268
•
270
271
272
274
119. The Polisher,
276
120. Instruments used in Polishing, .
277
121. Cutting of Precious Stones other than the Diamond,
280
122. Forms in which Stones are often cut,
281
•
123. The Lathe at work,
283
124. Tools and other objects used by the Engraver of Hard
Stones,
285
125. Apparatus for sawing Hard Stones,
287

DIAMONDS
AND
PRECIOUS
STONES.
PART I.
PRECIOUS STONES: their Origin; Geological Position; Physical
Characteristics; Optical and Electrical Properties; External
Characteristics; Susceptibility to the action of Light and Heat.
"The jewel that we see, we stoop and raise;
But that we do not see, we tread upon,
And never think of it.'
IN the following pages we intend to treat not
merely of precious stones strictly so called-that is,
such mineral substances as have in all times at-
tracted the attention of man by their hardness,
their brilliancy, their colour, their scarcity, &c., but
also of a certain number of productions which have
nothing in common with the true precious stones,
either in composition or origin, but which as articles
of finery and adornment play precisely the same
part as the latter.
When we contemplate the boundless wealth of
nature we might imagine that the number of precious
1

2
PRECIOUS STONES.
stones would be unlimited; but this, as we shall
see, is far from being the case. We must remark,
however, that it is impossible to draw a hard and
fast line between the most common precious stones
and ordinary stones, since we have here a particular
case of the grand law formulated more than a
century ago by the illustrious Linnæus: Natura
non facit saltus—“ Nature never makes a leap."
ORIGIN OF PRECIOUS STONES.
All precious stones are transparent, or at least
translucent, from which it may be concluded that
the matter of which each consists is homogeneous.
Now this homogeneity could never have been
attained by the mixture of their elements in the
solid state, however finely these may have been
pulverized, and hence they must have been in the
condition of either gases or liquids. Nature has a
multitude of means by which these transformations
of matter are effected, all referable to three general
processes:
Ist. Direct fusion of the substance by the action
solely of heat.
2d. Dissolution of the substance by the aid of
foreign substances at variable temperatures.
3d. Bringing together, in the state of vapours, sub-
stances destined to become the elements of the stone.

Fig. 1.-Igneous Rocks; the Volcano of Jorullo, in Mexico.

ORIGIN OF PRECIOUS STONES.
5
From the point of view of their formation, there-
fore, precious stones may be naturally divided into
two classes.
The first comprehends stones produced by direct
fusion, by crystallization in an excess of their
melted substance, by volatilization of their elements;
in a word, by the direct intervention of heat.
The second includes stones which have been
formed in the midst of a solution of which water
has been generally one of the constituent elements.
Hence some precious stones are met with in those
portions of our globe which have been subjected
to a high temperature, while others are found in
those that have never supported such a temperature,
or what comes to the same thing, that have been
perfectly cooled at the period when they furnished
to the water the elements of the stones of which we
are speaking.
It is therefore of some importance to distinguish
those portions of our globe which have been sub-
jected to the action of fire from those that have not;
and this is easily done.
GEOLOGICAL POSITION.
When we consider the solid part of our globe
we recognize immediately its division into earth,-
using that word in its agricultural sense; and stones

6
PRECIOUS STONES.
-more or less detached, or in the state of continu-
ous rocks. The least examination shows further,
that this earth itself is composed to a great extent
of stones gradually decreasing in size; so that we
easily arrive at the well-established conclusion that
the earth and the stones have the same origin.
If then, in thought, we remove from the surface
of the land the earth, whose thickness indeed is
very inconsiderable, we perceive that the solid part
of our globe consists exclusively of rocks.
These rocks are divided into two great classes:
one formed of melted materials, like the lavas of
our modern volcanoes; the other produced by seas,
rivers, and lakes of ancient periods, in the same
manner as we see deposits accumulated by the
waters in our own time. The first are called igne-
ous rocks; the second, sedimentary.
The Igneous Rocks, pushed from the interior of
the earth in a plastic state, lift themselves above
the surface of the soil in irregular shapes, in pre-
cipitous peaks, or vast cones, and sometimes in
those basaltic columns whose aspect is so striking
and impressive.
The accompanying cut exhibits a good example
of these basaltic rocks, but we may remark that
columnar basalt is comparatively rare, and that
igneous rocks in general possess no regularity of
structure. Very frequently they are intersected by
i


GEOLOGICAL POSITION.
7
cracks in all directions-a feature produced by the
contraction resulting froom cooling.
The Sedimentary Rocks present an aspect so
Fig. 2.-Horizontal Columnar Basalt at St. Helena.
completely different from that of igneous forma-
tions, that they may be recognized at a great dis-
tance, even by inexperienced eyes. Being deposited
in water in parallel layers, they have preserved the
same disposition after being left dry. Sometimes,
indeed, the horizontal layers have been singularly
displaced from their original direction: sudden
changes and movements of the soil have tilted them
up and contorted them; but still the parallelism of

8
PRECIOUS STONES.
the strata, and their disposition by successive layers,
is nearly, always clearly discernible.
Fig. 3 is an
Fig. 3.-Structure of Sedimentary Rocks.
example of sedimentary rock, and it shows very
distinctly the regularity of structure which these
rocks usually display.
Beyond this general distinction there is another,

GEOLOGICAL POSITION.
9
less prominent perhaps, but quite as definitely
marked. The remains of myriads of animals and
a
b
Fig. 4.-Trilobites.
a, Paradoxides bohemicus. b, Phacops latifrons.
Fig. 5.-Lyell's Cephalaspis.
plants have been left age after age in the sediments
of the different eras; these remains are known as
Fossils. They reveal forms of life very different
Fig. 6.-Calamite. Fig. 6ª.-Lepidodendron of the Coal Formation.
from those that exist in the present condition of our
globe; and their dominant races, long since extinct,

IO
PRECIOUS STONES.
have furnished names for remote eras,-for all the
geological ages, indeed, included between the azoic
age and the age of man.
With the high temperature of the igneous forma-
tions, life was incompatible; consequently no fossil
SALLE
Fig. 7.-Fossil Dragon-fly of the Secondary Epoch.
ever appears, or possibly could appear, in rocks of
this kind. In sedimentary formations, on the con-
trary, such remains abound, and furnish another
excellent means of distinguishing them from the
igneous rocks.
A few illustrations will exemplify types of animal
and vegetable fossils incident to different periods.

GEOLOGICAL POSITION.
II
Figs. 4, 5, and 6 represent animal and vegetable
forms that existed in a period incalculably remote,
Fig. 8.-Turrilites catenata.
Fig. 9.-Terebratula.
Fig. 10.-Mammillary Ammonite.
and are found in rocks belonging to what has been
called the primary or palæozoic period.
Those represented by Figs. 7, 8, 9, and 10 ap-
pertain to the secondary formations, such as the

12
PRECIOUS STONES.
oolite or jurassic formation, named from the Jura
Mountains, in whose rocks such specimens are
Fig. 11.-Cerithium
thiara.
Fig. 13.-Cancellaria
cancellata.
Fig. 12.-Gigantic Cerithium.
found; and the cretaceous period, or period of the
chalk, next in order of time.
To the cretaceous period succeeded the tertiary

GEOLOGICAL POSITION.
13
formation, in which are found such shells as those
represented by Figs. 11, 12, and 13. By this time
creatures had begun to appear bearing a strong
Fig. 14.-The Great Palæotherium.
resemblance to those of the present period. Figs.
14 and 15 illustrate characteristic types.
After the tertiary formation comes the post-ter-
tiary or quarternary formation, in which the animals
are quite analogous to those of our own period.
If we inquire of chemistry what is the composi-

14
PRECIOUS STONES.
tion of the two grand classes of rocks above-men-
tioned, we obtain this simple answer:-The calcare-
ous element predominates in all sedimentary for-
mations (excepting the most ancient); silicious and
aluminous elements in igneous formations.
CHORD
Fig. 15.-The Common Anoplotherium.
Consequently, stratification, presence and often
extreme abundance of fossils, great preponderance of
the calcareous element, are the unmistakable char-
acteristics of sedimentary formations. Absence of
stratification, complete absence of fossils, great pre-
ponderance of the silicious and aluminous elements,
are the characteristics of igneous formations.
Now if we investigate the chemical composition of
precious stones, we shall find that the greater num-
ber of those which really merit this appellation, are
GEOLOGICAL POSITION.
15
principally formed of silica and alumina, or of one
of these two substances. It follows, then, that
precious stones should be found most frequently in
igneous formations, or in the débris of such forma-
tions: and we naturally conclude that they will
be most abundant in countries where the geological
development is chiefly of this kind. Theoretically
this is true; but practically the finding of precious
stones depends far more upon the condition than
upon the abundance of the igneous rocks. These
eagerly sought treasures are only the very rare ex-
ceptions in enormous masses of rock, and the latter
must be broken up into small fragments before their
riches can appear.
We know that under the influence of atmospheric
agencies the most obdurate rock is gradually dis-
integrated; but atmospheric action has feebly con-
tributed to the production of sands and the for-
mation of arable lands. In different periods of its
existence our globe has experienced agitations of
extreme violence, the principal effects of which,
after the lapse of countless centuries, are at this day
perfectly discernible.
The last of these grand commotions belongs to
the period which geologists have named the quar-
ternary, an epoch relatively not far removed from
our own.
Floods of water at that time spread across the
16
PRECIOUS STONES.
continents; mountains of ice, of which the Alpine
glaciers are but meagre vestiges, invaded even the
most temperate zones; streams of irresistible violence
-such as the great rivers of our day can scarcely
give us any idea of furrowed the earth. Under
the influence of these agencies, the stupendous
forces of which were all working in one direction,
the grinding down and destruction of the rocks was
effected over vast spaces, and to considerable depths.
Now it is precisely in the débris of igneous rocks,
whose reduction to sand was accomplished during
this period, that the greater number of precious
stones are found; and above all, the diamond.
But although the diamond-producing soils are
comparatively modern alluvial formations, it must
not be concluded that the diamond, and the other
precious stones which accompany it, are of recent
origin. In reality, that which is recent is the reduc-
tion of the rocks to the alluvial state; but the rocks
themselves, and consequently the precious stones
that they contain, are often extremely ancient.
There are precious stones whose existence was
anterior to the first sedimentary formations; they
had their place in the world long before the plants
and animals began their measureless succession;
and they are an inheritance to man from the azoic
age, when as yet no foreshadowing of his existence
had fallen upon the globe.

PHYSICAL CHARACTERISTICS.
17
PHYSICAL CHARACTERISTICS OF PRECIOUS
STONES.
WEIGHT AND MOLECULAR ACTION.
Specific gravity.-Every one knows that two
equal volumes of different substances have seldom
the same weight: a piece of lead, for instance, is
much heavier than a piece of wood exactly equal to
it in size. If we find the weight of a substance, and
also that of an equal volume of another substance,
selected as a term of comparison (distilled water is
the term that has been chosen), and if we divide the
weight of the first body by that of the second, we
obtain a number which expresses how many times,
and fractions of times, the body considered is more
or less heavy than that to which it is compared.
The number thus obtained is its specific gravity.
In the case of precious stones it is a characteristic
of extreme importance, for it is frequently the means
by which the difference is detected between stones
that the eye might easily confound. In this way,
for example, the diamond can be at once distin-
guished from the zircon, the specific gravity of the
former being 3'4, and that of the latter 44
Hardness.-We should be careful not to fall into
the very frequent error of confounding the quality
of hardness with that of resistance to crushing or
2

18
PRECIOUS STONES.
concussion. There are minerals that may be crum-
bled between the fingers, and that are yet none the
less hard. The hardness of a substance, according
to the definition of Delafosse, is "the resistance
which it opposes to the action of a point like that
of a steel needle which may be drawn across it, or
to the angular part of another mineral passed with
friction over its surface."
Hardness is an indispensable quality of gems.
If a stone were not very hard, the continual friction
to which it is subjected would very soon destroy its
polish; and with the polish, transparency, brilliancy,
fire-all that constitutes its value-would vanish.
It is owing to this quality of hardness, added to
the unchangable nature of their substance, that
stones, cut perfectly by Egyptian artists thousands
of years ago, have reached us intact; and give us the
most interesting proof of the progress in arts and
civilization which had been attained in those remote
periods.
Fusibility.-Fusibility is the property which solid
bodies possess of passing into the liquid state, when
they are subjected to a sufficient temperature.
For precious stones in particular the point of
fusion is lower in proportion as the composition of
the stone is more complex. Thus the diamond, a
simple body, is absolutely infusible. The ruby, the
sapphire, the topaz, binary bodies, can only be

OPTICAL PROPERTIES.
19
melted before the oxyhydrogen blowpipe. The
simple silicates, ternary bodies, are fusible at a much
lower temperature; and the multiple silicates offer
no serious resistance.
The temperature of fusion of precious stones,
since it is allied in a remarkable manner with their
hardness, serves as a good characteristic for distin-
guishing them.
OPTICAL PROPERTIES.
Refraction. When a luminous ray passes through
a homogeneous medium, its course is in a straight
line, as shown in Fig. 16, a phenomenon with which
everyone is familiar. But when it passes from one
medium into another, the case is generally different,
and the ray suffers a remarkable modification. It
is then more or less diverted from its primitive
direction, and has the appearance of being broken,
whence the phenomenon has been termed refraction.
A stick plunged into water will exemplify this
effect.
The extent to which the luminous rays are
diverted in traversing transparent bodies varies
greatly. This variation is generally connected with
differences in the nature and composition of the re-
fracting bodies; but it is likewise intimately con-
nected, as experiments prove, with the molecular

20
PRECIOUS STONES.
constitution of these bodies. For example, Iceland
spar and aragonite, whose chemical composition
is identical, both consisting of pure carbonate of
lime, refract the light unequally, for the sole reason
that their molecular constitution is very different.
Fig. 16.-Course of a luminous ray in a homogeneous medium.
Double Refraction.-Among diaphanous bodies
there is a numerous class of substances that possess
the curious quality of presenting two images of one
object. If a crystal of Iceland spar is placed upon
a piece of white paper bearing an inscription, as in
Fig. 17, two images will be visible of every point,

OPTICAL PROPERTIES.
21
and both images will show deviation. This is an
instance of what is called double refraction.
When a body, crystallized or not, is perfectly
homogeneous in all its parts, so that its elements
are disposed everywhere in a uniform manner, one
can easily understand that the light must traverse
it regularly, and must present a single image of
every object: such bodies possess the property of
simple refraction.
Doubles REFRACTION DU SPATH
Fig. 17.-Double refraction of Iceland spar.
Crystals belonging to the monometric or tesseral
system, as the cube or octahedron, since their mole-
cular disposition is perfectly regular, never exhibit
the phenomenon of double refraction, in whatever
direction they are traversed by the light; but crys-
tals of all other systems possess the power of
double refraction, differing in its effects as the crystal
appertains to a system more or less closely related
to the regular system.
As all precious stones that are highly valued are

22
PRECIOUS STONES.
crystallized, and it has been well ascertained what
stones display simple and what stones double refrac-
tion, it sometimes becomes a matter of importance
to know whether a given stone is really doubly-
refrangent, in order to distinguish it from one which
possesses simple refraction, but to which in other
respects it is quite similar in appearance. As
precious stones are all small, a special method of
procedure is here necessary in order to obtain the
phenomenon of double refraction.
Take, for example, a small stone, cut in form of a
brilliant, concerning whose nature there is some
doubt.
Place the stone at a level with the eye, holding it
in one hand; in the other hand take an object of
small dimensions, a pin for instance, and move it
slowly on the other side of the stone until the
eye is able to perceive it. If the stone is doubly-
refractive, the rays will bifurcate on entering it, and
accordingly two images of the pin will be seen, if it
is not held too near the stone. If it is held
very
near the stone, the rays will not be far enough
apart at the point where they emerge into the air
to allow their separation to be evident.
If the experiment is made at night, instead of a
pin a lighted candle may be used, the candle being
placed beyond the reach of currents of air, so that
its flame may be pure and regular. The pheno-

OPTICAL PROPERTIES.
23
menon will be exactly the same, and have the aspect
presented by Fig. 18.
If the phenomenon of double refraction is pro-
duced, the conclusion may be made without hesita-
tion that the stone tested is not a diamond; for the
diamond, since it appertains to the cubic (mono-
Fig. 18.-Aspect of a candle seen through a doubly-refractive crystal.
metric) system, possesses simple refraction. The
stone experimented on, therefore, is no doubt one
of those with which the diamond is sometimes con-
founded, such as the sapphire and the zircon, which
possess double refraction.
Polarization.-It is well known that if a beam of
light falls upon a plane and polished surface it is re-

24
PRECIOUS STONES.
flected; but it is not so well known that if to this
ray, which has already been reflected at a certain
angle, a second mirror with plane inclined is pre-
sented, there are certain positions in which the ray
will be no longer reflected by the second mirror.
The light has acquired by its first reflection a pro-
found modification, which is designated by the name
of polarization by reflection.
In traversing certain crystals the light is sub-
jected to the same changes; that is to say, the rays
emerging from the crystal are no longer reflected
when they fall at a certain angle upon a plane
mirror; and they have become completely powerless
to traverse certain crystals, otherwise perfectly trans-
lucid, when the latter are presented to them accord-
ing to a determinate direction. The phenomenon
thus presented is polarization by refraction.
Double refraction and polarization are qualities
of crystals which are most intimately connected;
and the combinations of these two manifestations
produce magnificent phenomena of colouring, un-
attainable by substances producing simple refraction.
It is very easy, by aid of a polariscope, to be assured
upon the instant whether a precious stone possesses
or not the power of double refraction.
Dichroism, polychroism, asteria.-The pheno-
mena designated by these expressions, and which
give a magical beauty to certain precious stones,


ELECTRICAL PROPERTIES.
25
are entirely due to the refraction and polarization
of light. They show that the substances in which
they are produced have not identically the same
constitution in all their parts.
ELECTRICAL PROPERTIES.
In a general manner, all bodies acquire electricity
by friction; only, one kind keep for a longer or
shorter time the electricity confined as it were in
their pores, while the other kind lose it instantly.
The first are isolating bodies, the others are conduct-
ing bodies.
Precious stones belong to the first of these cate-
gories; but they exhibit great difference in the time
during which they remain electrified; and this
characteristic affords, in experienced hands, a very
useful test for distinguishing one from another.
There are certain precious stones which possess
the curious quality of becoming electric when they
are subjected to heat. The tourmaline is especially
susceptible to this thermotic electricity.
When precious stones are rubbed with the same
material, usually a bit of cloth, some of them acquire
positive electricity and the others negative electri-
city. Tourmaline, and other substances electrified
by heat, usually exhibit positive electricity at one
extremity and negative at the other.

26
PRECIOUS STONES.
OUTWARD CHARACTERISTICS.
TRANSPARENCY.
Transparency is the property that precious stones
possess of being more or less easily traversed by
luminous rays.
They are transparent when, being interposed be-
tween the eye and an object, they allow all the out-
lines of this object to be seen with perfect clearness.
Example: the diamond.
They are semi-transparent when the objects viewed
through them are a little confused. Example: the
emerald.
They are translucid when nothing can be per-
ceived when they are placed before the eye, but
that the light evidently has a passage through them.
Example: the chalcedony.
Finally, they are opaque when not a ray of light
can penetrate them. Example: the jasper.
LUSTRE.
"Among minerals great differences are met with
as regards the manner in which the light acts upon
their surface. In this respect there are two separate
effects to be distinguished, lustre and colour, which
are one to the other as timbre is to sound in a


OUTWARD CHARACTERISTICS.
27
musical instrument. Colour depends upon the
nature of the reflected rays, lustre upon their inten-
sity, and upon certain particular modifications of
their tint which cannot be defined; it depends upon
the structure of the body, its kind of texture, and
the greater or less polish of its surface. Lustre,
like colour and transparency, is susceptible of gra-
dation; it is more or less vivid, more or less dull;
and disappears entirely in varieties in which the as-
pect is rough, stony, or earthy" (Delafosse).
Adamantine lustre.-Intermediate between me-
tallic lustre and vitreous lustre; it belongs to cer-
tain crystals; to the zircon, and above all to the
diamond.
Nacreous or pearly lustre.-A mixture of silvery
and vitreous lustre, resembling, as its name indicates,
the nacre of pearl. Certain varieties of corundum
possess this lustre in a very pronounced manner.
Silky lustre.-Due to straight fibres disposed
very closely and of equal thickness. It resembles
the sheen of certain fabrics of mohair.
Oily lustre.-The stones which possess this lustre
are generally vitreous stones, which always seem,
even when newly fractured, to have been impreg-
nated with oil..
Resinous lustre.-A medium between the oily
and the vitreous lustre. The opal generally presents
this aspect.

28
PRECIOUS STONES.
Vitreous lustre.—This lustre recalls exactly the
fracture of glass. It belongs generally to bodies in
which the refracting power is inconsiderable.
ACTION OF LIGHT AND HEAT UPON PRECIOUS
STONES.
Light. When the most valuable precious stones,
and the diamond particularly, are exposed for a
certain time to the rays of the sun, and are then
taken into darkness, they remain luminous, and ex-
hibit the phenomenon of phosphorescence. This
curious effect lasts for some time, but gradually
becomes fainter and fainter, and finally dis-
appears.
Heat.-The effects produced upon precious stones
by heat are even more remarkable than those due
to the action of light. Heat acts upon them in two
very dissimilar ways. It modifies the elementary
constitution of the stone by separating its molecules,
but this in a manner altogether mechanical; or it
produces in the stone a veritable chemical reaction.
In the first case the modifications are temporary,
and at length the objects return to their primitive
condition; in the second case the effects produced
are permanent.
As an example of the latter case, we may cite a
practice whose origin is lost in antiquity, and which

ACTION OF LIGHT AND HEAT.
29
is still resorted to daily by lapidaries. It consists
in submitting a coloured stone (diamond, topaz, &c.)
to a temperature more or less elevated. Nearly
always in these conditions the stone changes colour
permanently.
A remarkable communication made to the
Academy of Sciences will serve as an example
of the first case.
'MM. Halphen have the honour to present to the
Academy a diamond of the weight of 4 grammes
(about 20 carats), presenting a phenomenon which
has never been before observed, at least to their
knowledge.
"This stone is, in its normal state, of a white
colour, faintly tinged with brown. When it is sub-
jected to the action of fire, it acquires a very clear
rose-tint, which it retains for eight or ten days, and
which it loses gradually, to return to its primitive
normal colour.
"This change and return to the primitive state
may be repeated indefinitely, for the diamond sub-
mitted to the Academy has been subjected five
times to this test.
"The phenomenon in question arrested at first
the attention of an observer, who was trying at
random upon this diamond the prolonged action of
fire. Experiments made since upon other diamonds
have not produced the same result.

30
PRECIOUS STONES.
}
"This question of colouring diamonds has an im-
portance which the Academy will easily appreciate,
when it considers that the stone presented at this
moment has, in its normal state, a value of 60,000
francs, while its price in the rose-coloured state, if
the colour were permanent, would be from 150,000
to 200,000 francs."

PART II.
Historical Survey of Precious Stones.
Ideas entertained by the
Ancients, and in the medieval age, concerning the Nature and
Properties of Precious Stones. Their Classification based upon
the analysis of Modern Chemistry.
"Though the same sun with all-diffusive rays
Blush in the rose, and in the diamond blaze,
We prize the effort of His stronger power.
And justly set the gem above the flower.”
Brilliant objects have from time immemorial
proved wonderfully fascinating to men.
No won-
der then that precious stones, those sparkling "blos-
soms of the rock," to whose rare beauty nature has
added the crowning gift of durability, should have
kindled a passion for possession and inspired ardent
search.
In our own day the exceptional value of gems
depends simply upon their use as ornaments, and
their service in certain important optical and other
instruments. With the ancients their importance
rested on very different grounds. They attributed
to these peerless little objects the most extraordi-
nary gifts; they ascribed to them a spiritual as well
as material potency—a power alike to cure diseases,

32
PRECIOUS STONES.
to avert calamity, and to drive away the demons of
the air.
The belief indeed came to prevail, that the pre-
siding genius of a man's fate might be carried about
with him in the shape of a precious stone. This
superstition, though to us it appears so absurd, was
Fig. 19-Egyptian Scarabæus cut in hard stone.
quite in accordance with the general views which
then prevailed regarding the moral and physical
worlds.
"A fact that governs all ancient history," says
Hoefer, in his Histoire de la Chimie, "is the close
alliance of religion with science. This alliance is
one of the distinguishing characteristics of antiquity:

HISTORICAL SURVEY.
33
in it is found the solution of many of the problems
that have disturbed the human mind."
It is this dominating fact that offers a key to the
special history of precious stones.
Among the grand false or mistaken ideas held
by the ancients, there are two that deserve all the
attention of the historian and the philosopher. The
first led them to consider man as a microcosm
reduction in miniature of the entire universe, a 'little
world' in exact counterpart of the 'great world.'
Accordingly every part of man's body was believed
to have a corresponding part in the vast universe.
At
The second was the conception of the soul of the
world, according to which the souls of animated
beings were but parts of the universal soul.
the moment of the dissolution of the body, said
the philosophers of India, the soul, âtmâ, very dif-
ferent from the merely vital principle, will unite
itself, if it is pure, with the great universal soul,
paramâtmâ, from which it emanated. If it is im-
pure it will be condemned to submit to a certain
number of transmigrations, that is to say, to ani-
mate successively plants or animals, or even to be
incarcerated in some mineral body until, purified of
all imperfections, it is considered worthy of absorp-
tion, mukti, into the Divinity.
Thus minerals as well as animals and plants were
to these philosophers living beings.
8

34
PRECIOUS STONES.
•
They maintained also, that the world was an
animal reuniting the two principles, active and
passive; an idea that entered fundamentally into
nearly all the systems of ancient philosophy.
From India these theories passed into Egypt,
whence they were transported to Greece by Plato,
Pythagoras, and other philosophers. Confined for
centuries to the European orient, they reappeared
Figs. 20 and 21.-Egyptian Figures carved in hard stone.
with some brilliancy at the commencement of the
present era in the writings of philosophers of the
school of Alexandria. In the medieval age, when
the alchemists transported them into the mineral
kingdom, they reigned supreme.
If we examine, in connection with these ideas,
the rank that was ascribed to precious stones, we
shall find that they necessarily acquired a great im-
portance. The beauty of their forms and the splen-
dour of their colours could not fail to make them
"

HISTORICAL SURVEY.
35
to be considered productions of an incomparable
purity, and an epitome of all that nature held most
perfect. To endow these mar-
vellous products with properties
in conformity with the prevailing
idea of their nature and origin
was but a step farther, and accord-
ingly we find attributed to them
talismanic virtues and agencies
of the utmost potency.
"It would not be without in-
terest," writes Babinet, "to follow
the history of gems through that
of humanity, from the ephod of
Aaron to the pastoral cross of
the Archbishop of Paris; from
the offerings of rubies, sapphires,
emeralds, diamonds, topazes, sar-
donyx, amethysts, carbuncles, and loadstones in
Fig. 22.-Cornelian en-
graved: Egyptian.
Fig. 23.-Egyptian Ring of Cornelian.
the temples of Jupiter and other pagan divinities,
to the riches of the same nature which by the

36
PRECIOUS STONES.
sixteenth century had accumulated in what was
called the 'treasury' of Christian churches. There
is still preserved at Rome an emerald of Peru, sent
in homage to the pope after the conquest of that
country. It should be remarked, however, that
these precious stores, originating in the piety of the
:

DISTA
ધા
A
if
Figs. 24 and 25.-Egyptian Rings and Tablets engraved on both sides.
faithful, have not always been faithfully respected.
When the reformation of Luther and Calvin in
German countries, and later, the French revolution
in countries remaining Catholic, transferred these
votive riches to the possession of the civil authorities,
it is well known that many fraudulent substitutions
had been made, and that paste had frequently
replaced the primitive gem."

HISTORICAL SURVEY.
37
Com-
"Precious stones," continues Babinet, "have in
all times been highly esteemed, and without doubt
will continue to be so in all ages to come.
paring our modern luxury with the splendours of
oriental courts and of Roman citizens enriched with
the spoils of the world, we find ourselves inferior in
many points, but not so far as diamonds are con-
cerned. If in one of the brilliant réunions of the
Tuileries, we calculate the value of the diamonds,
even allowing deduction for false jewelry, we con-
clude that our French riches, although more widely
spread, do not fall a whit behind the much-vaunted
riches of Rome." And this remark applies with
equal justice to the brilliant assemblies of other
modern capitals.
The mythology of India refers to precious stones
in terms that prove their general estimation in the
most ancient ages: the songs and ballads of that
country frequently mention these beautiful produc-
tions.
In Egypt a number of gems finely cut and en-
graved with consummate skill have been found be-
side mummies in tombs attributable to an extremely
remote era. Their workmanship leads to the belief
that the means employed by the ancient Egyptians
in engraving hard stones did not differ sensibly.
from those used at the present day.
Types of these ancient jewels, copied from speci-

38
PRECIOUS STONES.
mens in the museum of the Louvre, are represented
by Figs. 19 to 25. Fig. 22 is particularly interest-
ing; it is a red cornelian bearing hieroglyphic char-
acters, exquisitely engraved.
The conquerors of Mexico found in the hands of
the Incas a multitude of gems, cut and engraved
with various images, which, according to Mexican
traditions, had descended from a very remote
period.
In the Bible there are several passages that refer
with technical distinctions to precious stones. The
most remarkable occurs in the description of the
vesture of the high-priest, which was made, as the
Scripture reads, "for glory and for beauty," and
was adorned with symbolic gems. The ephod of
Aaron was ornamented with two onyx stones, en-
graved with the names of the twelve tribes of Israel.
The breast-plate consisted of twelve precious stones,
set in the form of a double square, and of a size
that allowed each stone, with its setting, to occupy
a space of 234 ins. by 2 ins.
Translators differ in their rendering of the Hebrew
names applied to these sacred stones-a fact which
need not surprise us when we consider how few
particulars are given-but the following order,
although differing somewhat from the arrangement
of Calmet, is in accordance with the opinion of
the most celebrated rabbis.

HISTORICAL SURVEY.
39
Order of the Stones in Aaron's Breast-plate.
I
2
Primus
Ordo.
Oden.
Cornelian.
REUBEN.
Phideth.
Topaz.
SIMEON.
3
Barcketh.
Emerald.
LEVI.
5
Secundus
Ordo.
Nophecth.
Saphir.
Ruby.
Sapphire.
6
Faolam.
Diamond.
JUDAH.
ISSACHAR.
Zebulun.
Tertius
Ordo.
7
Leschem.
Hyacinth.
DAN.
8
Schebo.
Agate.
NAPHTALI.
9
Achlamah.
Amethyst.
GAD.
IO
II
12
Quartus
Ordo.
Tarschisch.
Chrysolite.
ASHER.
Schoham.
Faspeh.
Sardonyx.
Jasper.
JOSEPH.
BENJAMIN.
In the book of Job there are facts mentioned that
have led some to attribute to the author a profound
knowledge of metallurgy; and he mentions by name
the precious stones, sapphire, onyx, ruby, and topaz;
crystal also, and coral and pearls. Mention is also
made of geological phenomena similar to those
which have played a part in bringing these mineral
treasures to light, and which are so familiar to the
geologists of the present day.
"He putteth forth his hand upon the rock; he
overturneth the mountains by the roots; he cutteth
out rivers among the rocks, and his eye seeth every
precious thing. He bindeth the floods from over-
flowing, and the thing that is hid bringeth he forth
to light."

40
PRECIOUS STONES.
In the New Testament the most remarkable
passage in which precious stones are mentioned is
that in the Apocalypse describing the New Jeru-
salem. "And the building of the wall of it was of
jasper," we are told, "and the foundations of the
wall of the city were garnished with all manner of
precious stones." The precious stones were twelve
in number, and they were arranged in order as
below, where each has its colour placed opposite to
it.
Order of Precious Stones in the Wall of the New Jerusalem
(Vision of St. John).
Jasper
•
Dark opaque green.
Sapphire (lapis lazuli)
Chalcedony
•
Opaque blue.
Greenish blue.
•
Emerald
•
Bright transparent green.
Sardonyx
White and red.
•
Sardius
Chrysolite
•
•
Bright red.
•
Bright yellow.
Beryl
Topaz (or Peridot)
Chrysoprasus.
•
Hyacinthus (Sapphire)
Amethyst
•
Bluish green.
Yellowish green.
Darker shade of same.
Dark shade of azure.
Violet.
In the Iliad and Odyssey there are occasional
metallurgic descriptions of much interest; and
especially to be noted in regard to precious stones
are the passages descriptive of the jewels of Juno.
MEDICAL MINERALOGY.

From the time of his first appearance upon the
earth, man has been subject to malady and death.
That is to say, medicine is as old as humanity.

ASTROLOGICAL MINERALOGY.
41
It is probable that the earliest medicines were
derived from vegetables, and that certain animal
substances were next made use of; but it was long
before people thought of employing mineral sub-
stances in medicine. This we first hear of in early
Greek history.
Certain earths, generally aluminous, administered
in various ways, were said to produce salutary
effects. These earths were sold in little packages
marked with different names, generally referring to
the places of their origin. They were rendered still
more efficacious by having a special seal affixed to
them by the priests of various divinities, whence the
term terra sigillata (sigillum, a seal). Among the
most celebrated of these "sealed earths" was the
earth of Lemnos, sold by the priestesses of the
temple of Ephesus, in packages stamped with a
goat, the sacred seal of Diana.
In the ancient pharmacopoeias, precious stones
are counted among the most valuable remedies.
Special virtues were attributed to the ruby, topaz,
emerald, sapphire, and hyacinth, which were ren-
dered famous in medicinal annals under the title of
"The Five Precious Fragments."
"
ASTROLOGICAL MINERALOGY.
Astrological mineralogy had its origin in Chaldea.
A work of Abolays, translated by Jehuda Mosca

42
PRECIOUS STONES.
!
about the middle of the thirteenth century, contains
a catalogue of 325 stones, distributed by the Chal-
dean astronomers among the twelve signs of the
zodiac, according to the relationship supposed to
exist between the different stones and the constel-
lations.
Later a single stone was specially consecrated to
each sign of the zodiac, and consequently to each
month of the year.
An amulet was made of these twelve sacred
stones; so that as the constellations appeared suc-
cessively above the horizon, the corresponding gems
might always be on hand, to convey to the possessor
the benign influences which they were then sup-
posed to bestow.
The following list comprises the twelve stones of
the amulet, with their zodiacal signs and the months
of the year to which they corresponded:-
Garnet.
Amethyst.
Jasper.
Sapphire
Agate
Emerald
•
•
Aquarius
Pisces.
•
Aries
Taurus
•
Gemini
•
Cancer
•
Leo
•
January.
February.
•
March.
•
•
April.
May.
June.
July.
Onyx
Cornelian.
Chrysolite
Aquamarine
Topaz
Ruby
·
Virgo.
Libra.
•
Scorpio
Sagittarius.
Capricornus
August.
September.
October.
November.
•
December.

It is exceedingly probable that the origin of this
superstition is to be traced to the twelve precious

ASTROLOGICAL MINERALOGY.
43
stones contained in the breast-plate of the Jewish
high-priest.
Traces of sacred, poetic, astrological, and medi-
cal mineralogy frequently appear collectively, or in
turn, in the treatises-even the most scientific-
that, from the time of Homer until now, have been
written upon precious stones.
Herodotus, born 484 years before Christ, five
centuries after Homer, has left us a great number
of statements, and some of them very valuable,
concerning mineral substances known in his time:
but he does not make mention of any new substance
appertaining to the class of precious stones.
In the poems of Orpheus, attributed also to
Onomacritus, and, in any case, as old as 450 B.C.,
there is evidence that the Greeks already attributed
supernatural qualities to precious stones.
In the following century Plato, whose vast intel-
ligence embraced so many transcendental ideas,
was led to examine the origin of precious stones.
He believed that they were veritable living beings,
produced by a sort of fermentation determined by
the action of a vivifying spirit descending from the
stars. He described the diamond, which he distin-
guished from other precious stones as being a kind
of kernel formed in gold; and supposed that it was
the noblest and purest part of the metal that had
condensed into a transparent mass.

44
PRECIOUS STONES.
Aristotle, born just a century after Herodotus,
touches upon minerals only incidentally, at the
end of his four books on Meteors, and sheds upon
them no new light.
Theophrastus, a pupil of Aristotle, wrote a trea-
tise upon precious stones, only a part of which has
reached us. Notwithstanding the defects of this
work, in part attributable to the times and in part
to the author, we are none the less indebted to
Theophrastus for the description of a number of
important mineral substances unknown before his
time.
We find also in this writer an idea which, taken by
itself, is very singular: he divides the stones into two
categories-male and female. When the reader
remembers what has been said above, however, he
will understand that there is nothing in this idea
that is not in harmony with the general ideas of
the ancients.
Dioscorides, whose valuable writings appeared in
the first century of our era, furnishes, in a minera-
logic point of view, no information of importance.
But in another aspect his works are exceedingly
interesting, seeing that we find in them the full de-
velopment of the idea that precious stones possess
a multitude of secret virtues-an idea admitted
without dispute by all his successors, to a time very
closely approaching our own, and which we find
ASTROLOGICAL MINERALOGY.
45
still entertained by the inhabitants of the moun-
tainous regions of Spain and Arabia.
A few years after Dioscorides a work appeared,
beyond all comparison in advance of its prede-
cessors, the Natural History of Pliny. In this
work, one of the most precious that we have in-
herited from antiquity, we find a chapter exclu-
sively devoted to precious stones: it is a chapter to
which we shall find occasion to refer in the follow-
ing pages.
Leaving Pliny we must come down to the Arabs,
ten centuries afterwards, before we find any new
information upon minerals and precious stones.
This we meet with first in the writings of Gerbert
and Avicenna.
Avicenna acquired in his lifetime a wide reputa-
tion; and although it was due as much to his tact
as to his science, it remained unrivalled for many
centuries.
*
Among his writings there is a treatise upon
stones, which comprehends results of great impor-
tance. The chapter devoted to the origin of moun-
tains deserves particular notice. It is in this chapter
that the learned Arab, always maintaining the
hypothetical method of argument, expounds with an
extraordinary grandeur and clearness of insight the
theory of upheavals, that of Neptunism and of
Plutonism, and the mode of formation of alluvial
•

46
PRECIOUS STONES.
•
deposits: thus anticipating by eight centuries the
results of modern science.
Two hundred years after Avicenna there ap-
peared one of the grandest figures of the middle
ages-Albertus Magnus, or Albert the Great.
Among the great works that we owe to this gifted
man, or at least to his impulse and direction, is a
treatise upon minerals, of which the illustrious
chemist M. Dumas has said, "That which charac-
terizes the treatise De Rebus Metallicis is the
learned, precise, and often elegant exposition of
the opinions of the ancients and of the Arabs; it
is the methodical discussion of these which discloses
at once the practised writer and the attentive
observer."
In this treatise Albertus Magnus discusses precious
stones; and while devoting a considerable space to
the extraordinary properties of these beautiful pro-
ductions, he carefully distinguishes a certain number
of them, and indicates methods of obtaining several
sorts of false gems.
Another illustrious genius of the middle ages-
the friend and disciple of Albertus Magnus-St.
Thomas Aquinas, whose voluminous works even
surpass in extent those of his master, has written a
treatise upon the Nature of Minerals, in which
some very curious passages occur, especially on the
fabrication of artificial stones.

ASTROLOGICAL MINERALOGY.
47
In glancing over the works of Arnault de
Villeneuve, of Raymond Lully, of Paul of Cano-
tanto, of Isaac the Hollander, &c., we find a certain
amount of space devoted to precious stones; but no
new idea worthy of note. Thus the end of the
fifteenth century is reached, and we emerge from
the medieval age.
Upon the threshold of the Renaissance a sin-
gular character appears, Jerome Cardan (born in
.1501), who furnishes us with some valuable sugges-
tions. Several works of Cardan, published after his
death, contain some rather absurd passages; but
in his treatise De Subtilitate, the careful student
finds many ideas which prove that the author pos-
sessed great intelligence, and beneath an air of
bonhommie a veritable sagacity.
•
Cardan designates under the generic name of
gems all the brilliant stones, and reserves the name
of precious stones for those which are not only
brilliant, but rare, and of small dimensions. These
precious stones he divides into three classes: Ist,
those which are brilliant and transparent, as the
diamond; 2d, those which are opaque, like the
onyx; 3d, those which are formed by the con-
junction of the two other kinds, as the jasper.
This is very nearly the same classification as
that employed by Caire, three centuries after
Cardan.

48
PRECIOUS STONES.
According to Cardan, precious stones are engen-
dered (“in the same manner as the infant from the
maternal blood") by juices that distil from precious
minerals in the cavities of the rocks: the diamond,
the emerald, and the opal from gold; the sapphire
from silver; and the carbuncle, the amethyst, and
the garnet from iron.
In enumerating the flaws or imperfections which
may be presented by precious stones, he makes a
remarkable reflection, and one which has been con-
sidered an ingenious plea for excusing certain well-
known imperfections of his own.
"In precious stones," he says, "imperfections are
in reality less common than in animals and vege-
tables; but they are more conspicuous in jewels,
simply because their nature is more brilliant and
more rare. For the same reason, great men appear
to have more vices than common mortals; but this
is a delusion and an error. The lustre of their
fame and the splendour of their names render their
faults only the more apparent; while the ignorant
vulgar, under favour of their obscurity, escape
having their vices noticed."
!
It was admitted without question, in the time of
Cardan, that precious stones were living beings.
And not only do precious stones live, but they
suffer illness, old age, and death."
He then speaks of the different virtues possessed

ASTROLOGICAL MINERALOGY.
49
by precious stones. The hyacinth preserves from
thunder-storms and from pestilence, and induces
sleep. This last quality was attributed to it by
Albertus Magnus. Without precisely rejecting this
notion, Cardan confesses that he carries ordinarily a
very large hyacinth, and that it has never appeared
to contribute anything towards making him sleep;
but he adds immediately, and with perfect naïveté,
that his hyacinth has not the true colour, and may
possibly be far from good. It was also believed
that the hyacinth increased riches, augmented
power, fortified the heart, brought joy to the soul,
&c.
He describes the turquoise, which, mounted in a
ring, secures the horseman from all injury if he falls
from his horse; and adds, "I have a beautiful tur-
quoise which was given me for a keepsake, but it
has never occurred to me to test its virtues, as I do
not care, for sake of the experiment, to fall from
my horse."
It is not necessary to multiply examples to give
an idea of the remarkable properties ascribed to
gems in antiquity, and in the middle ages. In
discussing this subject M. Babinet makes the fol-
lowing striking remarks:—
"For all maladies of a nervous or moral nature,
where imagination might exert a great influence,
precious stones were certainly a sovereign remedy.
4

50
PRECIOUS STONES.
In saying to such an invalid that an emerald placed
under his pillow would drive away melancholy, dis-
pel nightmare, calm the palpitations of the heart,
induce agreeable thoughts, bring success to enter-
prises, and dissipate the anxieties of the soul, a cure
was certain to be effected simply by the faith which
the invalid had in the efficacy of the remedy. The
hope of cure in such affections is the cure itself; and
in all the numerous cases where the mind has had
an influence upon the bodily system, the imaginary
cause must produce a very real effect. Finally,
that eternal deception of the human spirit, which
registers all the cures, but does not take into ac-
count the cases where the curative means have failed
of their end, contributed to maintain the belief in
the occult virtues of precious stones. It is not half a
century ago since sufferers would borrow from rich
families gems mounted in rings, to apply to afflicted
parts. When the trinket was introduced into the
mouth as a cure for toothache, sore throat, or ear-ache,
the precaution was taken to secure it with a strong
thread, lest it should be swallowed by the patient.
"It is unnecessary to say that if we are asked to-
day, whither are gone all these beliefs which to our
fathers were incontestable, we answer that they are
gone with the 'lunar influences' so powerful in the
time of Louis XIV., to take their place in the
vast limbo of human errors."

CLASSIFICATION.
51
It remains to us now to say a few words concern-
ing the order that we shall follow in the particular
description of precious stones.
In spite of all the discussions that have arisen on
this subject, and the great number of classifications
presented by different authors who have occupied
themselves with the question, there does not exist,
and there cannot exist, any general and natural
classification of precious stones. The reason is very
simple: these substances being what we may call
particular cases in nature, it is not possible to arrange
them in series. By choosing any one of their
general characteristics, crystalline form, refraction
single or double, composition, or commercial value,
&c., the geometrician, the physicist, the chemist,
and the merchant can easily establish a classification
answering more or less completely to their special
end; but this is not a natural classification.
Without discussing or criticizing the different
methods proposed, we shall adopt in this book a
classification based upon chemical composition.
If there should be placed upon a table a specimen
of every kind of precious stone known at the present
day, it would be possible to separate them imme-
diately, according to their chemical composition,
into three perfectly defined groups.
The first comprises a single precious stone, the
diamond. Its constituent principle is carbon.

52
PRECIOUS STONES.
The second includes the sapphire, the ruby, the
topaz, the amethyst, the emerald, &c.-stones of
which alumina is the base.
The third comprises stones whose base is silica-
the opals, the agates, &c.
Carbon, alumina, silica: this is the order of im-
portance of the three substances which enter essen-
tially into the composition of precious stones; and
in this order we shall arrange the chapters devoted
to the history of all the gems which each division
includes.
But before studying these groups, two descriptive
terms applied to precious stones should be explained,
the terms Oriental and Occidental.
Originally these words were applied in their
literal sense; but at the present time they are re-
tained in commercial parlance, not to indicate the
regions from which the precious stones are brought,
but simply to establish between stones of the same
name a comparative value. The most precious
variety of any precious stone is called Oriental, and
the inferior variety Occidental, whatever may be the
countries in which they are found.

PART III.
"Le Diamant! c est l'art de choses ideales,
Et ces rayons d'argent, d'or, de pourpre et d'azur
Ne cessent de lancer les deux lueurs égales
De pensers les plus beaux, de l'amour le plus dure.”
The diamond, which for a long time has been
considered the most precious of gems, has been
known from early antiquity.
Its name adamant, a name that can be recog-
nized in nearly all its modern appellations, was given
by the Greeks, and signifies "the indomitable."
The excessive hardness of the diamond quite
justifies this designation; but we find from the
authors of antiquity that the ancients attributed to
this stone certain other properties that it can by no
means lay claim to, such as that of not becoming
warm when heat was applied to it, and above all,
that of resisting, without breaking, the blow of a
hammer. The latter property is mentioned both
by Lucretius and Pliny, not to go farther back.
“Adamantina saxa
Primâ acie constant, ictus contemnere sueta."
"The test of all these diamonds," says Pliny, "is
made upon an anvil by blows of the hammer, and
their repulsion for iron is such that they make the

54
PRECIOUS STONES.
hammer fly in pieces, and sometimes the anvil
itself is broken." This error maintained its ground
down to a very late period. Thus in the year 1476,
when, after the battle of Morat, the Swiss soldiers
seized upon the tent of Charles the Bold, they
found in it, among other treasures, a certain num-
ber of diamonds, and in order to test whether they
were genuine struck them with hammers and
hatchets, and of course broke them in pieces.
•
The diamonds earliest known to the Romans
were furnished by Ethiopia; but when Pliny wrote,
during the first half century of our era, they had
already been brought from India; and thencefor-
ward, until the eighteenth century, no diamond mines
were known but those of the East Indies-in the
empire of the Mogul, and in the island of Borneo.
Then the discovery of the Brazilian diamond dis-
tricts created an excitement throughout the world;
and, considerably more than a century afterwards,
the opening of the diamond-fields of South Africa,
has once more "revolutionized the trade.”
In 1829, in accordance with a judgment ex-
pressed by Humboldt, diamonds were found in the
Ural Mountains; they have also been obtained from
Sumatra, Java, South Carolina, Georgia, Alaska,
Arizona, Mexico, and Australia; but the production
has been of too isolated occurrence to indicate any
new. centres of commerce.
1

DIAMOND MINES OF INDIA.
: 55
The accepted diamond countries of history and
commerce are India, Brazil, and South Africa.
DIAMOND MINES OF INDIA.
First of all, for size and beauty, the Indian dia-
monds are famed: "diamonds of Golconda" have
become a synonym for preciousness and brilliancy.
These gems were brought, not from the immediate
vicinity of the fortress of Golconda, but from the
mines of Raolconda and other localities situated
in the territory of the Golconda kings. The mines
were many years ago ceded to the English, but
they have long since been abandoned; and it is
believed that they are exhausted. Their treasures,
however, shine in the coronets of every nation of the
globe.
Diamond localities are numerous in Hindostan,
and in Borneo, whose "Landak" diamonds have
been especially prized; but many of these localities
have ceased to be productive, and their names are
becoming obsolete. In Tavernier's time the Gol-
conda mines employed 60,000 people, and had
already proved so rich that, as Ferishta records,
the Sultan Mahmoud (A.D. 1177-1206) left in his
treasury more than four hundred pounds weight of
these precious gems.
It is from the descriptions of Tavernier, a

56
PRECIOUS STONES.
French jeweller who travelled through Turkey,
Persia, and the Indies in the latter part of the seven-
teenth century, that we derive the most vivid accounts
of the Indian mines.
"I visited first," he writes, "a mine in the terri-
tory of the kings of Visapoor, in a place called
Raolconda, five days from Golconda, and eight or
nine from Visapoor.
"All around the place where the diamonds are
found the ground is sandy and full of rocks, and
covered with coppice, somewhat like the environs of
Fontainebleau. In these rocks are numerous veins,
sometimes half a finger, sometimes a whole finger
wide; and the miners have little iron rods, crooked
at the end, which they thrust into the veins to dis-
lodge the sand or earth in which the diamonds are
found.
After this part of the work is done,
the earth and sand is passed through two or three
washings, and is carefully searched to see if it have
any diamonds. It is from this source that the
clearest stones and those of finest water are taken.
The only evil is, that to render more easy the ex-
traction of the sand from the rocks, such strong
blows are given with a great lever of iron, that they
shock (étonne) the diamond and produce flaws."
Tavernier visited also the mine of Garree, seven
days east from Golconda, and the diamond-yielding
bed of the river Gooel, in the kingdom of Bengal.
:

DIAMOND MINES OF INDIA.
57
He relates, with very picturesque and lifelike de-
tails, his various affairs with the diamond mer-
chants; and announces the somewhat remarkable
fact, that the chief negotiators in the sale of dia-
monds in India were boys not over sixteen years
of age.
"It is pleasant," says Tavernier, "to see the chil-
dren of these merchants, and of other people of the
country, from the age of ten to that of fifteen or six-
teen, coming every morning and seating themselves
under a large tree in the market-place of the town.
Each has his diamond weights in a little pouch hang-
ing at one side, and at the other side a purse attached
to his girdle, and containing, in some cases, as many
as six hundred gold pagodas. There they sit and
wait until some one comes to sell them diamonds, it
may be from the vicinity, or from some other mine.
When anyone comes with something for them he
places it in the hands of the eldest of the boys, who
is, as it were, the chief of the band. He looks at it, and
hands it to the one next him, and so it passes from
hand to hand till it return to the first, not a word
being spoken by any of them; the eldest boy then
asks the price, in order to make a bargain, if pos-
sible, and if he happen to buy it too dear he has to
take it on his own account."
When evening comes the boys bring together all
the stones they have bought, examine them, and

58
PRECIOUS STONES.
5
arrange them according to their water, their weight,
and their clearness. Then they put upon each its
price, as near as possible that at which they would
sell to the merchants, and by the latter price they
see how much profit they will have. They now
carry them to the large merchants, who have al-
ways great numbers of stones to assort, and all the
profit is divided among the boys, the one who acts
as their chief receiving one-fourth per cent. more
than the others. Young as they are, adds Taver-
nier, they know the price of every stone so well
that if any of them have made a purchase, and is
willing to lose a half per cent., another will give
him his money.
He describes the devices resorted to by jewel-
dealers to conceal any defects there might be in
their merchandise; and the skilful manner of plan-
ning the cutting so as to dispose of flaws.
From the very moment of its recognition, it
would seem that the diamond quickened the wits of
its possessor, and aroused an ambition of brilliant
gain. Even the poor slave in the mines managed
occasionally to elude the sleepless vigilance of the
overseers, and conceal a valuable gem. Tavernier
saw in one of the Indian mines a poor wretch who, to
appropriate to himself a fine diamond of the dimen-
sions shown in Fig. 27, had forced it into the corner
of his eye in such a way as to conceal it completely.

Fig. 26.-View in a Diamond District of Brazil.

DIAMOND MINES OF BRAZIL.
61
According to Heynes' account of the mines of
Hindostan, the diamond is found in alluvial soil, or
the most recent rocks. "Shallow pits are exca-
vated to the diamond beds, which lie about eight
Fig. 27.-Size of a Diamond hidden by a slave in the corner of his eye.
feet below the surface of the soil, in a conglo-
merate of rounded stones under two distinct layers;
the
uppermost, a mixture of sand, gravel, and loam;
and the other, thick black clay or mud."
DIAMOND MINES OF BRAZIL.
Brazilian diamonds are found in the district of
Minas Geraes, at San Paulo, in the beds of various
rivers, and at Serro Frio, or Cold Mountain, a
lofty plateau measuring eight leagues by sixteen.
The most productive districts of late are Matto
Grosso and Bahia.
The diamonds occur usually in alluvial soil, en-
veloped in a conglomerate formed of rounded white
quartz pebbles and light-coloured sand. The miners
have names for each variety of soil; as-
Grupiara, the unused bed of a river.

62
PRECIOUS STONES.
:
Burgalhoa, angular fragments of rocks that strew
the ground; and
Cascalho, the generic name of all.
When diamonds were first found by the gold
hunters of Brazil, no notion was formed of their
value. They were used for counters in card-play-
ing. But at last a native named Bernardo Lobo,
who had journeyed to the East Indies, and had
seen uncut diamonds there, recognized the nature
of these disregarded pebbles.
The news of the discovery spread across the
world, and its first effect was a panic in the dia-
mond trade. Some time had to elapse before the
dealers in Indian gems could reconcile themselves
to any rival that might depreciate the treasures of
the Orient.
Meanwhile upon the inhabitants of the diamond
districts the discovery acted like a curse; and to
the bitter sorrows of persecution were added the
horrors of earthquake and drought. "It seemed as
if the genii," says Emmanuel, "guardians of the
treasure, were indignant at the presumption of
man, and tried by every means to prevent the dis-
persion of the buried treasure."
But the riches of the province were incalculable.
The search for gold no longer offered any attrac-
tion; the children gathered the precious dust after
the rains. The energies of the gold-hunters were

Fig. 28.-First wash of the Diamond-yielding Soil in Brazil.

DIAMOND MINES OF BRAZIL.
65
diverted to diamond finding; care was taken even
to examine the crops of all kinds of killed fowls,
for diamonds had been found in this way; a negro
found a gem of five carats adhering to a cabbage
which he had plucked for his dinner.
As the search became organized, the waters of
the rivers were diverted at the dry season into canals.
The soil was dug to the depth of about ten feet, and
deposited in heaps near the washing huts. These
huts were furnished with elevated seats for the over-
seers, who watched incessantly the long troughs,
called canoes, in which the cascalho was washed.
When a slave found a diamond of 18 carats he
received his freedom, and was crowned with flowers,
and led in a triumphal procession, amid the rejoicings
of his friends.
Modern appliances and innovations have altered
somewhat the primitive modes of diamond washing,
but the leading features remain the same, the object
being to wash away the finer particles of soil, and
obtain the gems from the residue.
In 1754, a slave, transported from Minas Geraes
to Bahia, discovered, from analogies of soil that led
to immediate diamond-seeking, the wonderfully rich
district of Bahia. It is now estimated that the
Brazils export annually from Rio Janeiro an amount
of rough diamonds averaging in value from four to
five millions of dollars
5

66
PRECIOUS STONES.
DIAMOND MINES OF SOUTH AFRICA.
In the autumn of 1868 news reached England
from Capetown that diamonds had been found in
the gold districts on Orange River, midway between
the eastern and western coasts of South Africa.
And in the spring of the following year all doubts
that had been either genuine, or instigated by
jealous fear of disturbance in the diamond trade,
were silenced by the discovery of the "African
Koh-i-noor," valued at about $150,000.
This splendid stone, destined to create a stir that
should widen into the most distant circles, was
found by a poor herdsman, who had the supreme
happiness to dispose of it for five hundred sheep,
ten head of cattle, and a horse. It was taken to
Capetown, where an injunction was placed upon it
by emissaries of Waterboer, chief of the Griquas,
who claimed it as the possession of his own terri-
tory; but, for lack of proof, the injunction was re-
moved, and the diamond finally reached England.
From that time tidings of new discoveries became
more and more frequent; and the Griquas began
successfully to search the beds of their streams.
By 1870 public attention had become thoroughly
aroused. Already enterprising men and capitalists,
among them Coster of Amsterdam, were on the

DIAMOND MINES OF SOUTH AFRICA.
67
field. The diamond districts of the Vaal had
proved an entire success. Seventy-two large dia-
monds were found at Pniel in one week; ninety-one
were unearthed by a single digger within a fortnight;
diamonds to the amount of $500,000 had been
picked up by Europeans.
A regular organization of diggers was formed
near the mission station of Pniel,-itself, as after-
wards proved, one of the richest localities. A
(6
digging committee" apportioned to each man so
many square feet, to be worked at once or aban-
doned. The diamond claims of these "dry dig-
gings" came eventually to be sunk sixty feet below
the surface; sometimes seventeen feet of red sand
was removed before diamondiferous soil could be
reached. The best yield occurred generally at the
depth of twenty or twenty-five feet. The natives
worked in these pits with pick and shovel; above
them were the sorting-tables, some under cover,
some not; and between the crowded pits carts
crawled along, bringing burdens of gravel to the
tables, to be sorted by the Europeans.
The excitement had now reached its height.
Not only did every town of South Africa empty it-
self of men for "the diggings," but diamond-hunters
made their appearance from every quarter of the
globe. There were forty thousand people within a
line of seventy miles upon the banks of the Vaal

68
PRECIOUS STONES.
River. Hotels, shops, music-halls flourished; two
newspapers were started. One after another new
diamond-fields were brought to light. Du Toit's Pan,
De Beers, Pniel, New Rush, and Colesberg Kopje
opened their dazzling mines.
:
The rival claims of different routes from the
coast were contested with the utmost zeal. Rail-
ways and telegraphs were projected, and modern
machines were hastened to the scene. The mines
were pronounced the richest in the world. Dia-
monds weighing from 20 to 30 carats were not
unusual; and among the exceptional treasures
found were diamonds weighing considerably more
than 100 carats; including the beautiful "Star of
Beaufort," and the "Star of Diamonds," weighing
107½ carats; and a lovely stone, which attracted
especial attention by exhibiting, under the micro-
scope, an aspect of pointed mountain summits,
lighted by vivid sunlight with all the colours of the
rainbow. Rubies and turquoises were also found.
But all these successes were not unalloyed. There
were droughts, and fevers, and mournful death-lists.
There were threatened invasions of the Caffres that
kept all the white men armed; and frauds that
occasioned lynch-law mobs; and annoyances on the
frontiers. And there were endless disputes of
boundaries and territorial rights, not altogether
quelled when, to the joy of the miners, the British

DIAMOND MINES OF SOUTH AFRICA.
69
flag was hoisted on the diamond-fields, Nov. 1871;
and the district south and west of the Vaal, known
as West Griqualand, was proclaimed under the
protection of the crown.
The South African diamonds are found over
many hundred square miles of territory. The prin-
cipal diggings are situated in the extensive valley
of the Vaal river, to the north-east of the Orange
River Free State, and within the boundary of the
Cape Colony as now defined. The country here
rises into long stony ridges, called kopjes, consisting
of irregular fragments of hard rock imbedded in
ferruginous gravel, which varies in character and
compactness, being sometimes quite loose and
sometimes forming a compact lime-cemented mass.
It is in this gravel that the diamonds are found.
They occur at various depths down to twenty feet
or more, but the usual depth is from two to six feet
below the surface. "The manner of working is
simple enough. A claim, or piece of ground thirty
feet square, is occupied by two diggers in partner-
ship, assisted by their black servants. They re-
move the loose blocks of stone, which are cast aside;
they take up the gravel and sift it thoroughly,
either in a dry state, or with abundance of water in
a sieve rocked by a cradle. When the pebbles
have been thus separated from the sand, they are
cleansed, and placed upon the sorting-table to be
4

70
PRECIOUS STONES.
carefully examined for any diamonds that may lie
among them."
Some fears were entertained as 1872 opened with
still brightening prospects, that the large numbers of
stones found might produce a depreciation in value;
but such is the unprecedented demand for diamonds,
these fears have not yet been realized. The "off
colour" of South African diamonds only enhances
the value of the translucent and colourless stones of
Brazil and India; and their large size and extreme
brilliancy finds for them an ample appreciation. It
is estimated that the diamonds exported from
Capetown during the year 1871 amounted in value
to $7,500,000.
WEIGHT AND VALUE OF DIAMONDS.
The diamond is known in three different mole-
cular states, forming a graduated series that is very
remarkable. It is crystallized, crystalline, and
amorphous.
The crystallized diamond is the diamond "par
excellence;" it is that which, when cut, is used in
jewelry.
The crystalline diamond cannot be cut. It bears
in commerce the name of "boart," and is reduced
to powder for cutting crystallized gems.
The amorphous diamond is of a steel-gray colour

WEIGHT AND VALUE.
71
and quite opaque. It occurs in sandstone of very
old formation, and is found in Bahia, and of late in
Mexico. It has no utility when cut, but reduced to
powder it is used for polishing diamonds and other
gems, and is especially prized by the watchmakers
of Switzerland. Its hardness is identical with that
of the crystallized diamond; its specific gravity is
3'012 to 3'016. It is not used to so good advantage
in proportion to its weight as "boart." It is known
in commerce under the name of carbonate, or car-
bonic diamond.
Crystallized diamonds in their natural state are
called “rough diamonds."
The diamond is always sold by weight. The
standard of weight for all precious stones is the
carat; a name derived, it is said, from the seeds of
a pod-bearing plant used in the East to measure
gold dust. The carat is 4 grains; that is, diamond
grains, which differ slightly from troy grains, as it
takes five of the former to weigh four of the latter;
or more exactly, one carat = 3'174 gr. troy.
The carat is universally employed in the com-
merce of jewelry, but it is not rigorously the same
in all countries. The following are the weights of
the different carats in milligrammes:-
Brazil,
France,
England,
Holland,
Spain,
205'750
205'500
205˚409.
205'044
205'393

72
PRECIOUS STONES.
The carat is divided into, 1, 1, 1, 12, 24 of
the carat. The table of weights of a jeweller's
balance should contain from the weight of a thou-
sand carats to these fractions.
The balance employed by dealers in pre-
cious stones is a simple little balance which is
held in the hand: and yet "such is the experienced
quickness of the lapidary," says M. Helphen, “that
the balance of the assayer will never find him wrong
by even the 64th part of a carat."
Rough crystallized diamonds are valued at from
16 to 19 dollars the carat, for assorted lots containing
no diamonds of more than one carat. Above this
weight prices are a different affair.
The rule made known two hundred years ago by
Tavernier, that "the prices of two diamonds are
proportioned to the squares of their weights," is en-
dorsed by some modern lapidaries. According to this
rule, since a one-carat stone of the first water, well cut
and without flaws, is valued at about $93, a stone of
two carats should be worth four times that, or $372;
and one of three carats, nine times as much, or $837.
But statistics show that this rule, which was quite
true in the time of Jeffries and Tavernier, is no
longer applicable; it assigns to diamonds a higher
price than in commerce they really bring.
A table is given here, which not only establishes
this fact, but which also furnishes other interesting

WEIGHT AND VALUE.
73
conclusions. It is a table showing the prices of
diamonds in the years 1606, 1750, 1865, and 1867.
Comparative Values of DIAMONDS IN 1606, 1750, 1865, and 1867.
Brilliants.
1606.
1750.
1865.
1867.
Dols. cts.
Dols. cts.
Dols. cts.
Dols. cts.
½ carat,
¾
1 1
25 48
28 08
"
I
ΙΟΙ 37
37 57
44 26
84 25
14
""
172 42
58 59
131 31
51 52
-98 39
164 05
1/2
"
273 97
84 44
178 18
210 92
134
2
354 88
114 57
225 06
257 79
405 85
150 10
304 85
375
16
24
"
456 8x
189 53
328 29
422 03
2/2
234
3
34
3/2
334
"
558 55
234 36
453 46
516 15
761 48
283 27
468 90
562 65
"
914 37
337 59
586 08
656 39
"
632 95
703 26
""
1015 56
395 80
703 26
821 19
821 19
890 94
4
1219 04
459 42
1
44
1078 42
1125 30
4/2
1421 97
677 04
1172 17
1406 71
434
1312 97
1547 33
5
1624 71
937 81
1500 46
1641 07
VALUES OF DIAMONDS IN 1872
(A Table prepared by Mr. Hermann, President of the New York
Melée, per carat,
Diamond Company).
from $60 to $65
Melange,
$100 to $110
Value of Brilliants in CurrenCY.
Brilliants of
½ carat,
""
Brilliants of
$35
60
3 carats,
•
$500 to $550
34
I
11
100 to $125
3/2
700 to
14
"
150 to 175
334
600 to 650
750
800 to 850
1½
19
200 to 225
4
999 to 950
1¾
""
250 to
275
44
"
1000 to 1050
2
300 to 325
42
""
1100 to 1150
24
"
350 to
375
434
1200 to 1250
2/2
400 to 425
5
""
1399 to 1400
234
"
450 to
500

74
PRECIOUS STONES.
The prices of the preceding table refer only to
diamonds of the first quality, and without a flaw.
One sees immediately that the rule of Tavernier
is completely at fault. For by his rule the value of
the one carat, being estimated in 1867 at $98, 39c.,
a diamond of two carats should have been worth
$393, 56c., while in reality it brought $375, 16c.; and
a diamond of five carats should have been worth
twenty-five times as much, $2459, 75c., when it
brought actually only $1641, 7c.
Another point that strikes the attention in in-
specting this table, is the extraordinary depression
in the price of diamonds in the middle of the
eighteenth century. It was about that time that
the discovery of the diamond districts of Bahia
occasioned a panic in the diamond market.
Lastly, the table shows that, absolutely, the price
of diamonds was nearly the same in 1606 as in
1867; but when we take into account the difference in
the value of money at these two epochs, we see that
diamonds were really much dearer
at the beginning of the seventeenth
century than they are now.
Large diamonds are exceedingly
rare. It is estimated that among ten
Fig. 29.-Dimensions of
a Brilliant of 10 carats. thousand diamonds hardly one will
be found of ten carats weight; that is to say, of the
size represented by Fig. 29.

COMPOSITION OF DIAMOND.
75
1
COMPOSITION OF THE DIAMOND.
The ancients had no suspicion of the true
nature of the diamond. To have any idea of this
subject, it was necessary that the bases of modern
chemistry should be established, or at least that
the complex phenomenon of combustion should
have received its true explanation. Newton sus-
pected from its wonderful refractive power that the
diamond was combustible, but even as late as the
middle of the eighteenth century, the definition of
its composition, given in a standard work on physics,
was "the purest and finest earth, the most ethereal
fire, and the most limpid water."
The first important fact relative to the nature of
the diamond was established by Boyle about the
middle of the seventeenth century. He showed
that under the influence of a great heat the dia-
mond disappeared. A little later, in 1694, Cosmo
III., Grand-duke of Tuscany, had a diamond sub-
jected at Florence to the intense heat of the sun's
rays, by aid of a concave mirror. The experiment
was conducted by Averini, preceptor of the Prince
John Gaston, son of Cosmo, and Targioni, member
of the Academy del Cimento. The diamond first
split, then emitted sparks, and finally disappeared.

76
PRECIOUS STONES.
This experiment was repeated at Vienna by
Francis Stephen of Lorraine, afterwards Francis I.
of Austria. The sun's rays were replaced by the
fire of a furnace, with the same result. Nearly a
hundred years after the experiment at Florence it
was renewed in Paris by D'Arcet, Rouelle, and
Macquer. On the 26th of July, 1771, these savants
burned in the laboratory of Macquer a beautiful
diamond furnished by an amateur, Godfrey de
Villetaneuse. That the diamond had disappeared
was certain, but the question arose whether it had
actually burned or was merely volatilized.
In the midst of the discussion, Le Blanc, a cele-
brated jeweller of the day, ignoring the experiments
carried out at Florence, Vienna, and Paris, affirmed
that fire had no effect upon the diamond. He had
frequently, he said, submitted diamonds to a high
temperature to remove certain defects, and the heat
had never in the least degree deteriorated the
stone.
To prove his assertion he tried an experiment
before a great number of spectators in the labora-
tory of Rouelle. He enveloped a diamond in a
mixture of lime and charcoal dust, introduced it
into a crucible, and exposed it to a violent heat.
After about three hours the interior of the crucible
was examined, and nothing was found there but the
little box that the diamond had occupied. The
4

COMPOSITION OF DIAMOND.
77
experiment had resulted like the others, and Le
Blanc retired amid the acclamations of his op-
ponents, "without his diamond, but still uncon-
vinced."
Light had now begun to dawn upon the question,
but it was still far from being settled. Accordingly
Cadet, Macquer, and the illustrious Lavoisier made
preparations for new experiments on the subject,
when a skilful lapidary named Maillard presented
himself before them, and maintained, as Le Blanc
had done, that fire had no effect on the diamond.
He offered to submit three diamonds to the most
prolonged and intense heat, but he stipulated that
he should be allowed to carry out the experiment
in his own way.
This being granted, Maillard took the bowl of a
tobacco-pipe, placed the three diamonds in it in
the midst of charcoal powder closely packed, closed
the mouth of the pipe with a cover of iron, and then
shut up the whole in a crucible filled with chalk
and covered with a siliceous coating. (See Fig. 30.)
The crucible was now subjected to a temperature
such that at the end of four hours it was com-
pletely soft and on the point of melting, when the
fire was slackened. After the crucible had been
allowed to cool it was carefully broken open, the
pipe-bowl was found to be entire, with the char-
coal in it as black as at first; and in the midst of

78
PRECIOUS STONES.
this the three diamonds, in every respect unaltered
and uninjured.
Some diamonds prepared by Maillard, and sub-
mitted for twenty-four hours to the enormous tem-
Fig. 30.-Maillard's Experiment.
perature of a porcelain furnace, resisted the heat
like the preceding.
Analogous experiments were made in different
parts of Europe, sometimes with the one, sometimes
with the other of the preceding results. The facts
remained inexplicable till-on the principal pheno-

COMPOSITION OF DIAMOND.
79
mena of combustion being established-it was
noticed that the diamond had always disappeared
when it had been heated in the presence of air,
while it had undergone no modification when re-
moved from the action of the air by means of sub-
stances such as powdered charcoal, lime, &c.
Arrived at this stage, the question could not long
remain unsolved; and the solution was soon fur-
nished by two of the creators of the science of
chemistry-Humphry Davy in England, and La-
voisier in France.
"And what is the diamond?" asks Babinet, who
has such a quick eye to the poetry of science. "The
most precious thing in the whole world. And what
is carbon? The most common material that is
known; one that not only exists in vast quantities
in the bowels of the earth, but that plants and trees
of every kind contain, in an inconceivable quantity.
Silver can hardly pay for the diamond; for if we
imagine a diamond of the weight of a twenty-five
franc piece, it would weigh about 125 carats, and
cost at least four millions of francs; while an equal
weight of carbon, even having recourse to the
smallest copper pieces, would have no appreciable
value. And yet the diamond and carbon are iden-
tical. Diamond is crystallized carbon."
Everyone knows the pungent gas that escapes
from fermented liquors-cider, beer, wine, &c.-and

Ɛo
PRECIOUS STONES.
i
is introduced artificially into aerated waters. It is
formed by the combination of carbon with one of
the elements of the air (oxygen), and is called by
chemists carbonic acid. This substance is produced
whenever carbon, or substances which contain car-
bon, are burned in contact with the air; and not the
slightest trace of it is ever found, if the substance.
burned does not contain carbon.
After this grand fact had been established, it
was very easy to find out if the diamond contained
carbon, and also whether this was its sole constituent.
To settle the first question, the celebrated Lavoisier
had recourse to the experiment represented by
Fig. 31.
A bell-glass filled with oxygen was reversed in a
basin containing mercury. A cupel placed at the
extremity of a little column received the diamond,
upon which the sun's rays were concentrated by
means of a burning-glass.
The diamond disappeared; and it was proved
that the glass, which at the commencement of the
experiment had contained no trace of carbonic acid,
contained a great quantity after the disappearance
of the diamond. The diamond then contained
carbon as one of its elements. Davy did not remain
satisfied with this.
By analogous experiments he showed that the
combustion of the diamond in oxygen produced

COMPOSITION OF DIAMOND.
81
carbonic acid only; the diamond, then, must be com-
posed of carbon and nothing else.
Certain doubts still lingered upon this point, but
they were dispelled by the publication in 1841 of
BIBELTOUR
C.LAP 410
Fig. 31.-Combustion of the Diamond by Lavoisier.
the grand work of MM. Dumas and Stass upon
the equivalent of carbon.
In their experiments these two savants burned a
great number of diamonds, but they corrected an
error the maintenance of which would have been
a veritable calamity to science. The capital impor-
6

82
PRECIOUS STONES.
..
:
tance of the results obtained by MM. Dumas and
Stass completely justified the use of such ex-
ceptional fuel.
It is very probable that the absolutely pure dia-
mond consists exclusively of carbon; but perfectly
pure diamonds are very rare. All those burned by
MM. Dumas and Stass left a residuum or ash, if
we may call it so, sometimes in the form of a
spongy network of a reddish-yellow colour, some-
times as crystalline particles of a straw-yellow
colour, sometimes as colourless and crystalline frag-
ments. This residuum varied from go to zoʊ of
the weight of the diamond employed.
It used to be believed that the diamond could be
consumed only with great difficulty. This error is
corrected by one of the most fascinating experi-
ments of chemistry. It was first performed by M.
Morren, senior of the faculty of sciences
at Marseilles.
lllo
Fig. 32.
He took a wire of platinum, and by
means of a little cone of wood gave it
the shape represented by Fig. 32.
He then fixed the upper end of the
wire in a cork, and placed in the little
receptacle the diamond to be burned.
A phial filled with oxygen was at hand.
By aid of a blowpipe the temperature of
the diamond and its support was elevated to white

COMPOSITION OF DIAMOND.
83
heat, and then was plunged quickly into the phial
of oxygen (Fig. 33). The diamond immediately
kindled, and continued to burn with a steady glow
infinitely more vivid than that which could have
been obtained from any other variety of carbon.
Fig. 33.-Combustion of the Diamond in Oxygen.
M. Morren has also proved that the diamond
burns in layers: for if the combustion is arrested at
any period, the special system of crystallization is
still regularly displayed.
This is a very important point, since it excludes
all idea of fusion for the diamond.

84
PRECIOUS STONES.
CELEBRATED DIAMONDS.
It is from Asia, that cradle of luxury and splen-
dour, that most of the diamonds that have become
famous have been derived.
Tavernier gives a minute description of the dia-
monds of Aurengzebe, at whose court he was
favourably received, and whose jewels he was per-
mitted to inspect and weigh.
"The first stone," he writes, "that Akel-Kau
placed in my hands was a great diamond cut as a
rose, very high on one side. It had a slight notch
on one of its edges, and a small flaw within. It was
of the first water, and weighed 280 carats." When
brought from the mine of Colore, near Golconda, it
weighed 787½ carats, but had several flaws. Hor-
tensio Borghis, a Venetian, was employed to cut it,
and the work nearly cost him his life; for the king
accused him of having spoiled the diamond, and
only allowed him the privilege of retaining his head
on the payment of ten thousand rupees. This dia-
mond is believed to be the same as that which now
belongs to Queen Victoria, and is known as the
Koh-i-noor. Its history will be given below.
"After having fully examined this beautiful
stone," continues Tavernier, "and having returned
it to the hands of Akel-Kau, he showed me another

CELEBRATED DIAMONDS.
85
diamond, finely formed, and of the first water, with
three table-cut diamonds, two clear, and one having
little black points. Each one of these weighed
from 48 to 50 carats; and the first 542 carats. He
then showed me a trinket consisting of twelve dia-
monds all roses, and each one weighing from 13 to
Fig. 34.-Diamond of the Rajah of Mattan.
14 carats. In the midst was a heart-shaped rose,
of first water, with three little flaws: this rose
weighed 35 carats."
One of the most celebrated diamonds is that of
the Rajah of Mattan, in Borneo. It was found on
that island, and weighs 318 carats.¹ It is shaped
1 Other accounts make the weight of this diamond 367 carats.

86
PRECIOUS STONES.
like a pear, and of the dimensions shown in
Fig. 34.
This diamond is considered by the people of
Borneo as a kind of palladium to which the
destinies of the empire are attached. They attri-
bute to it the miraculous power of curing all diseases
Fig. 35.-The Nizam.
by means of the water in which it has been dipped.
On one occasion, according to Jamieson, the gover-
nor of Borneo offered for it $150,000, two large war-
brigs with their guns and ammunition, a certain
number of guns, and a quantity of powder and shot.
But the rajah refused to part with it.
India has in its possession another famous dia-
mond, the Nizam (Fig. 35), a rough diamond
weighing 340 carats, and estimated at $930,000.
One of the most celebrated diamonds in the

CELEBRATED DIAMONDS.
87
world is the Regent or Pitt diamond. Its brilliancy
and proportions are considered matchless, and it is
also of considerable size. It was found in the mine
of Parteal, forty-five leagues south of Golconda, and
weighed in the rough state 410 carats. Two years
and $23,250 were spent in cutting it into a brilliant
ed bluoda
Fig. 36.-The Regent.
-a process which reduced it to 137 carats, but the
cutting is perfect.
The usual account given of this diamond is, that
it was bought at Madras by the grandfather of the
first Earl of Chatham, when he was commander of
Fort St. George; that he paid $60,000 for it, and
that it was bought in 1717 for $648,000 by the

88
PRECIOUS STONES.
Duke of Orleans, when regent of France during the
minority of Louis XV.
A very different story, however, is told by Saint-
Simon, who professes to speak of his own personal
knowledge.
He says that the diamond was stolen by a per-
son employed in the diamond mines, who escaped
to Europe with it, and after showing it to several
princes, and among the rest the King of England,
passed over to Paris and showed it to the somewhat
notorious Law. Law proposed to the regent that
it should be bought for the king, but the state of
the finances was such that the duke hesitated to
spend such a large sum in that way. Saint-Simon
lent his influence in favour of the purchase, repre-
senting that the diamond was peerless in Europe,
and would well become the crown of France, and
that the purchase of it would shed glory on the
regency of the duke. The latter at last consented,
and the diamond was bought for $384,000, the seller
receiving also the fragments resulting from the
cutting, with interest on the price until the whole
was paid.
From that time the Regent became identified
with the fortunes of France, and a chapter of his-
toric details belongs to its career. It has passed
through many revolutions, and it has passed-very
literally-through many hands; for in the days

CELEBRATED DIAMONDS.
89
that followed the fall of Louis XVI., the Regent,
carefully chained and guarded by gendarmes, was
exposed to the people of Paris; and any half-starved
workman who chose might hold this symbol of
royal splendour and epitome of twelve million francs
for a few moments in his brown hand.
The Regent-pawned to the Batavian govern-
ment by Napoleon I.-stolen by robbers, and its
hiding-place revealed at the gate of death by one
Fig. 37.-Empress Eugénie.
of the reckless band, and mounted in the state
sword of the first Napoleon-finally glittered in the
imperial diadem, through the palmy days of
Napoleon III.
Another beautiful diamond is the Empress Eu-
génie. It is cut as a brilliant, and weighs 51 carats.
A third famous diamond, belonging for some
time to France, is the Sancy. Its history is not
quite certain. According to some authorities it
was brought by an ambassador from Constanti-

90
PRECIOUS STONES.
nople; according to others, it ornamented the hel-
met of Charles the Bold, who lost it at the battle of
Granson. It was found by a Swiss soldier, who
sold it to a priest for two francs; it disappeared
then for some time, until, in the year 1589, King
Anthony of Portugal pledged it among other
stones to De Sancy, then treasurer of the King
of France, who retained it by paying 100,000 livres
. Fig. 38.-The Sancy.
(coinage of Tours). Henry III., after a lapse of
time, borrowed it for the purpose of pledging it to
the Swiss government; but the servant who was
carrying it to the king disappeared, and was not
heard of for some time. At last it was discovered
that he had been assassinated in the forest of Dôle,
and buried by the care of a charitable curé in the
cemetery of a village. "Then," said the Baron de
Sancy, "my diamond is not lost." In fact the gem
was found in the stomach of the servant, whose
CELEBRATED DIAMONDS.
91
fidelity had given him at the last moment the pre-
sence of mind to swallow it.
According to the inventory of 1791 the Sancy
weighed 331 carats. It excited especial interest
from the peculiarity of its cutting.
In 1792 the Sancy once more disappeared, and
was found by the police of Paris, through an anony-
mous letter, in the Champs Elysées. It is now in
Russia, and is valued at what M. Helphen con-
siders an exaggerated price, $186,000.
The crown-jewels of France, including the Re-
gent and the Sancy, contained in 1774, 7482
diamonds. This magnificent collection was stolen
in 1792.
The collection of Napoleon I., gathered from
every part of Europe, was superior to the old col-
lection, but inferior to the one subsequently made,
which contained 64,812 diamonds, in 1832, valued
at $3,887,848. After that time there was again an
increase in the number of the French jewels, in-
cluding the beautiful Empress Eugénie.
Within a year, according to statistics of 1872,
the Bonaparte family alone have thrown upon the
market diamonds to the amount of $1,210,000.
Brazil, rich in mines of precious stones, would
naturally be supposed to possess valuable jewels;
and in fact the crown diamonds of this empire are
valued at more than $18,600,000.

92
PRECIOUS STONES.
÷
Among the principal diamonds is that which, cut
in a pyramid, adorns the handle of the cane of
John VI., and is estimated at $162,192. Brazil has
furnished also the twenty diamonds which form the
twenty buttons of the doublet of ceremony of
Joseph I., each one of which is valued at $23,250; the
whole costume representing a sum of $465,000.
But the marvel among these productions of Bra-
zil is the Star of the South. This extraordinary
diamond was found in 1853 in the mines of Boga-
gan, by a poor negress. The rough diamond
weighed 257½ carats. It has been purchased by
M. Helphen.
This beautiful diamond has now been cut. It is
of an irreproachable purity, transparent, and taking
by refraction a lovely rose tint.
The Star of the South was cut at Amsterdam
in the establishment of M. Coster; and no better
example could be given of the difference between a
rough diamond and one that has been cut, than is
presented by Fig. 39, in which the different views
of the Star of the South, in its rough state, are
taken from drawings made by the illustrious miner-
alogist M. Dufrénoy. Figures are also given of the
diamond as it now appears.
Among the diamonds found in Brazil are three
famous stones belonging to the crown of Portugal.
The first is called the King of Portugal's dia-

CELEBRATED DIAMONDS.
93
mond. It was found in a place called Cay-de-
Mérin, near the little river of Malhoverde. Mawe
Fig. 39-Star of the South, before and after cutting.
GA
says that it weighs 1680 carats. And in Brazil its
value is estimated at $1,395,000,000. Only-it has

94
PRECIOUS STONES.
been suggested, that this diamond is a topaz, in
which case the millions vanish.
No one is allowed to behold this diamond, which
is still in the rough. And since the question of its
nature is not tested, it may be presumed that the
test is withheld for good reasons.
Of the value of the two other famous diamonds.
of Portugal there is no doubt. One weighs 215
carats, the other is flatter and weighs a little less.
These beautiful stones were found by three men
who were banished to the province of Minas Geraes,
and who bought their freedom with them.
The crown of England is very rich in beautiful
diamonds; its chief treasure is the famous Koh-i-
noor, or "mountain of light.”
The history of this stone is obscure, but, as al-
ready mentioned, it is believed to be the same gem
as that described by Tavernier among the jewels of
Aurengzebe. According to a Hindu legend it was
worn by one of the heroes of the Indian epic poem
the Mahabharata, and it would therefore have a
history extending backward about 4000 years.
Coming down to later times we find it in possession
of Vikramaditya, rajah of Ujayin, 56 B.C., from
whom it passed to his successors, the rajahs of
Malwa, and latterly to the sultans of Delhi, when
Malwa fell into their possession. Its later history
is given by Mr. Hunt as follows:-"Nadir Shah,

CELEBRATED DIAMONDS.
95
on his occupation of Delhi in 1739, compelled Mo-
hammed Shah, the great-grandson of Aurengzebe,
to give up to him everything of value that the im-
perial treasury possessed; and his biographer and
secretary signifies a peshkash or present by Mo-
hammed Shah to his conqueror of several mag-
Fig. 40.-The Koh-i-noor before re-cutting.
nificent diamonds. According to the family and
popular tradition Mohammed Shah wore the Koh-
i-noor in front of his turban at his interview with
his conqueror, who insisted in exchanging turbans
in proof of his regard. However this might have
been, we need have little doubt that the great dia-

96
PRECIOUS STONES.
mond of Aurengzebe was in the possession of Mo-
hammed Shah at the time of the Persian invasion;
and if it was it most certainly changed masters,
and became, as is universally asserted, the property
of Nadir Shah, who is also said to have bestowed
upon it the name of Koh-i-noor. After his death
the diamond, which he had wrested from the unfor-
tunate representative of the house of Timur, became
the property of Ahmed Shah, the founder of the
Abdali dynasty of Kabul, having been given to him,
or more probably taken by him, from Shahrikh,
the young son of Nadir. The jewel descended to
the successors of Ahmed Shah, and when Mr. El-
phinstone was at Peshawur was worn by Shah
Shujah on his arm. When Shah Shujah was driven
from Kabul he became the nominal guest and
actual prisoner of Runjet Sing, who spared neither
importunity nor menace, until, in 1813, he com-
pelled the fugitive monarch to resign the precious
gem, presenting him on the occasion, it is said, with
a lakh and 25,000 rupees, or about $60,000. Run-
jet was highly elated by the acquisition of the dia-
mond, and wore it as an armlet at all great festivals.
When he was dying an attempt was made by per-
sons about him to persuade him to make the dia-
mond a present to Jaganath, and it is said that
he intimated assent by an inclination of his head.
The treasurer, however, whose charge it was, re-
CELEBRATED DIAMONDS.
97

fused to give it up without better warrant, and
Runjet dying before a written order could be
signed by him, the Koh-i-noor was preserved for a
while for his successors. It was occasionally worn
by Rhurreuk Sing and Shu Sing. After the mur-
der of the latter it remained in the Lahore treasury
until the supercession of Dhulip Sing and the
annexation of the Punjaub by the British govern-
ment (1849), when the civil authorities took pos-
session of the Lahore treasury, under the stipu-
lations previously made that all the property of the
state should be confiscated to the East India Com-
pany, in part payment of the debt due by the
Lahore government, and of the expenses of the
war; it was at the same time stipulated that the
Koh-i-noor should be presented to the Queen of
England. Such is the strange history of certainly
one of the most extraordinary diamonds in the
world. After the Company became possessed of
the gem it was taken in charge by Lord Dalhousie,
and sent by him to England in custody of two
officers."
When the Koh-i-noor was brought to England
it weighed 186, carats, and had the form shown
in Fig. 40. It was exhibited in this state at the
Great Exhibition of 1851, and was valued at about
$700,000. At that time it was merely surface cut,
and was also disfigured with several flaws, so that

98
PRECIOUS STONES.
re-cutting seemed advisable; and it was decided to
give it the form of the brilliant. The cutting was
begun on July 16, 1852-the Duke of Wellington
being the first person to place it on the cutting
mill-and was finished Sept. 7, thus occupying in
all thirty-eight days of twelve hours each. It had
Fig. 41.-The Koh-i-noor after being re-cut.
now the form represented in Fig. 41, its weight
being reduced to 12234 carats. In cutting it some
parts were found to be very much harder than
others. Though so much reduced in weight by
this operation the Koh-i-noor has been much im-
proved in brilliancy and effect.
Besides the Koh-i-noor, and a great number of

CELEBRATED DIAMONDS.
99
fine pearls, the crown of Queen Victoria contains
497 diamonds, of which the value is estimated at
more than $372,000.
Fig. 42.-The Pigott.
Another well-known diamond is the Pigott, which
was brought from the Indies by Lord Pigott. Its
weight is 81% carats. It was sold by lottery in
1801 for the sum of $139,500. Later it became the
property of the Pasha of Egypt, who paid for it an
equal sum. Fig. 42.
Fig. 43.-The Nassac.
The Nassak or Nassac is a diamond of a triangular

AYLMER
Mechanics Institute
100
PRECIOUS STONES.
form, with curved facettes, belonging to the Mar-
quis of Westminster, who had it cut into its present
It weighs 785% carats, and is estimated at
about $148,000.
form.
The country that is most rich in diamonds at
present is Russia.
Besides special collections of diamonds in the
treasury of this empire, there are three crowns of
which they form the sole jewels. The first, that of
Ivan Alexiowitch, contains 881; that of Peter the
Great, 847; and that of Catherine the Great, 2536.
Fig. 44.-The Orlow.
Among the large diamonds in Russia the most
remarkable is the Orlow. It weighs 193 carats.
It has, as is shown by Fig. 44, the form of a half
egg. It is one of the ornaments of the imperial
sceptre.
T
This beautiful diamond was originally from India.
It formed for a century and a half one of the eyes

1 Carat
12
3/1/00
1
8
ม
44
34
2
3
3
3
314
6
22
24
25
8
28
14
20
30
Fig. 45.-Surface of Roses compared to their Weight.

CELEBRATED DIAMONDS.
103
of the famous idol of Serringham in the temple of
Brahma; the other eye was a diamond of the same
order.
At the commencement of the eighteenth century
the idea seized a French soldier of one of the French
garrisons in India to steal the eyes of this cele-
brated idol. He pretended to be inspired with a
wonderful zeal for the Hindu religion, and gained
to that degree the confidence of the priests that
Fig. 46.-The Shah.
He
they confided to him the care of the temple.
chose his time, and one stormy night carried off
one of the diamonds; the other could not be
forced from the socket. He fled to Madras, where
he sold the stolen treasure to a captain of the
English navy for $9300. Conveyed to England it
was bought for $55,800 by a Jewish merchant,
who sometime after sold it to Catherine II. for
$418,500, and a pension for life of 18,600.
It was this famous stone that suggested Wilkie
Collins' novel "The Moonstone."

104
PRECIOUS STONES.
Another beautiful Russian diamond is called the
Shah: it belonged once to the ancient monarchs of
Fig. 47.-The Polar Star.
Persia. It is of very excellent water, and weighs 95
carats. Fig. 46 shows the peculiar form of this
beautiful stone.
The third great Russian diamond is the "Moon
of the Mountain." It was bought for 50,000 piastres
Fig. 48.-The Grand-duke of Tuscany.
of an Afghan chief by an Armenian merchant
named Schafnass, who kept it for twelve years, and

CELEBRATED DIAMONDS.
105
then sent it by his brother to Amsterdam, where,
after a long negotiation, it was bought by Russia
for $334,800 and a patent of nobility.
Russia possesses also a superb diamond, the Polar
Star, cut as a brilliant, and weighing 40 carats. It
belongs to the Princess Youssoupoff. Fig 47.
The finest diamond owned by Austria is the
Grand-duke of Tuscany. It is a little yellow, and
is cut to represent a star of nine rays. Fig. 48.
This diamond belonged to Charles the Bold, who
lost it at the battle of Granson. Found by a
soldier, it was sold by a Genoese merchant to Ludo-
vic Sforza, duke of Milan. It became afterwards
the property of Pope Julius II., who presented it to
the Emperor of Austria. It weighs 1392 carats.
Fig. 49.-The Pasha of Egypt.
Egypt possesses a very beautiful brilliant of 40
carats, which bears the name of the Pasha of
Egypt. It cost $136,200.
In Holland there is a diamond of 36 carats, esti-

106
PRECIOUS STONES.
mated at $48,360; and one in the treasury of
Dresden that weighs 314 carats.
A black diamond was sold by M. Bapst to Louis
XVIII. for the sum of $4464, but it was never de-
livered. Its colour was a very dark brown, and it
had a remarkable lustre.
Fig. 50.-The Blue Diamond of Mr. Hope.
A precious stone without a rival is the blue dia-
mond of Mr. Hope. Its weight is 44% carats, and
its colour is the blue of the most beautiful sapphire,
added to an adamantine lustre of the utmost bril-
liancy. It was purchased for $83,700, but com-
petent judges declare that it is worth more.
ENGRAVING UPON THE DIAMOND.
Notwithstanding its wonderful hardness, the dia-
mond has been engraved.
In the Paris Exhibition of 1867, in the Italian
section, an engraved diamond was exhibited. It
-

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20
50
70
100
Fig. 51.-Surfaces of Brilliants compared to their weight. The vertical lines
indicate the thickness of the stone.

CELEBRATED DIAMONDS.
109
was engraved in the sixteenth century by Jacopo or
Como da Trezzo; and it was set in a unique cylin-
drical ring of gold, by aid of a movable collet
upon pivots.

PART IV.
Sapphire. Ruby. Balas Ruby. Spinel Ruby. Topaz. Emerald.
Cymophane. Turquoise.
Beryl. Aquamarine.
“What wonder then, if fields and regions here
Breathe forth elixir pure, and rivers run
Potable gold, when with one virtuous touch
Th' arch-chemic Sun, so far from us remotė,
Produces, with terrestrial humour mix'd
Here in the dark, so many precious things,
Of colour glorious, and effects so rare ? "
?
Every one knows that common substance called
clay, which is so easily mixed into a paste with
water. But every one does not consider perhaps
what an important part in agriculture and industry
this familiar substance performs.
All soils that are of value for the production of
vegetables contain clay. The principal element of
this substance-alumina-is necessary to the de-
velopment of plants; and its presence is necessary
to retain the humidity of soil that is indispensable
to vegetable life.
To indicate the importance of clay in the indus-
trial world it is only necessary to say that tiles,
bricks, pottery, from the coarsest kind to the finest
COMPOSITION.
III
Sèvres ware, are almost exclusively formed of this
substance.
And what is clay?
To answer this question categorically is impos-
sible, because there are comprehended under that
name a multitude of mixtures, whose composition
is extremely variable; but the only fact important
for us to know here is that the principal constituent
element of clay is alumina.
In these modern times industry has been en-
riched by an important conquest, aluminium, that
new metal which, whether used alone or in com-
bination with other metals, lends itself with com-
plete success to the manifold wants of the industrial
arts. It is a discovery and creation for which our
epoch is indebted to the French chemist M. Henri
Sainte-Claire Deville.
If this metal is combined with the oxygen of the
air, the metal disappears, and is transformed into
the rust of aluminium; exactly as the brilliant and
metallic iron is transformed into iron rust under
the same conditions; only that aluminium rust is
white instead of red. This white rust is pure
alumina.
Now this alumina exists in a prodigious quantity,
not only in vegetable mould, but also in a large
portion of the rocks of our globe. Generally it is
mixed with iron rust, which gives it a red colour, or
Um

II2
PRECIOUS STONES.
it may be with other substances; but it now and
then occurs in absolute purity; and it is always
possible to extract pure alumina from any kind of
clay.
If we ask now what is the composition of the
precious stones whose names figure at the head
of this chapter, we are answered-they are formed
of alumina nearly pure. Besides this they contain
only some faint traces of foreign matters, generally
of the oxide of iron.
Notwithstanding the minute quantities, these
foreign matters are very important, because it is to
their union with alumina that the precious stones
we are considering owe their remarkable colour, and
consequently a great part of their commercial
value.
But if the ruby, the sapphire, and kindred gems,
are formed almost exclusively of alumina, we must
hasten to add that this alumina is crystallized, for
in this fact is comprehended the cause of the enor-
mous distance which separates the alumina of the
soil around us from the alumina of which precious
stones are composed.
CORUNDUM.
Modern mineralogists have given the single name
corundum to all the minerals consisting of crystal-

CORUNDUM.
113
lized alumina almost pure, without regard to the
colour of these minerals.
Corundum comprehends three varieties: the hya-
line corundum, the laminated corundum, and the
granular corundum. The first variety comprehends
the precious stones.
The primitive form of the crystals of corundum is
the six-sided prism (Fig. 52), but the most general
form of the hyaline corundum is the dodecahedron
(Fig. 53), with faces formed of isosceles triangles.
Fig. 52.-Primitive form of
Corundum.
Fig. 53. Most common form
of the Corundum.
Nearly all the hyaline corundums susceptible of
being employed in jewelry are brought from Pegu.
The price of these stones is very high. It is not a
rare occurrence for the price of the ruby to exceed
8

114
PRECIOUS STONES.
that of the diamond. At an auction of precious
stones from the cabinet of M. Drée a very beautiful
diamond of 8 grains (2 carats) was sold for $148,
while a ruby of the same weight brought $186. At
the same sale the price of a ruby of 10 grains
reached $2604. The value of the ruby and that of
precious stones generally varies with their richness
of tone.
When the corundum is perfectly colourless it
possesses a brilliancy so vivid that in some circum-
stances it may pass for a diamond. It may be dis-
tinguished from the latter by its inferior hardness,
its smaller specific gravity (3'5, while that of the
diamond is 3'9), and by having double refraction.
According to the tints which the corundum pos-
sesses, it bears different names, and represents
variable values.
Names of the corundums according to their
colour:-
•
White Sapphire,
Oriental Ruby,
Oriental Ruby (variety), .
Oriental Sapphire,
Indigo Sapphire,
Oriental Amethyst,
•
•
•
Colourless.
Crimson red.
•
Rose red.
•
Azure blue,
Indigo blue.
Violet.
Oriental Topaz,
•
Oriental Emerald,
·
THE RUBY.
Yellow.
Green.
There exists but one true ruby, the oriental
ruby.
THE RUBY.
115
The spinel ruby and the balas ruby must be care-
fully distinguished from this valuable gem, as
neither in nature nor composition do they resemble
the oriental ruby.
"The oriental ruby," says Babinet, "ranks first
for price and beauty among all coloured stones.
When its colour is of good quality it has the vivid
tint of arterial blood (a tint called 'pigeon's blood'
in commerce), or of the very centre of the red ray
in the solar spectrum. It is the perfect red of the
painter's palette, without any mixture of violet or
of orange. Several of the reds in the stained glass
of our ancient cathedrals, when the daylight pours
through them, give an idea of this brilliant
colour.
"The ruby is extremely hard; and after the
sapphire, which surpasses it a little in this respect,
it is the hardest of precious stones, always ex-
cepting the diamond, to which nothing can com-
pare. M. Charles Achard, the highest authority
in France in all that concerns the traffic in coloured
stones, remarks that weight has not the same effect
in their case as in that of the diamond. Every dia-
mond, from the very smallest specimen upwards,
has its value like gold or silver, according to weight;
but in the case of rubies and other gems the little
specimens have hardly any value; and these stones
only begin to be appreciated at the moment when

116
PRECIOUS STONES.
their weight withdraws them from the common
ruck, and assures at once their rarity and high price.
When a perfect ruby of 5 carats enters the market
a price will be offered for it double the price of a
perfect diamond of the same weight; and if a ruby
reaches the weight of 10 carats it will bring triple
the price of a diamond of the same weight (from
three to four thousand dollars).
I have seen many collections of amateurs, visited
and consulted many lapidaries, and everyone admits
that a perfect ruby is the most rare of all the pro-
ductions of nature. The tint of the ruby is as
admirable by artificial light as by the light of day."
The precious stone called the carbuncle by the
ancients is the same as our modern ruby.
The most fantastic qualities were formerly as-
cribed to these wonderful stones. The carbuncle
served to furnish light to certain great serpents or
dragons when old age had enfeebled their eyes;
they constantly carried these magical stones be-
tween their teeth, only dropping them when it was
necessary to eat and to drink. And according to
St. Epiphanius the carbuncle has not only the pro-
perty of shining brilliantly in darkness, but its light
is of a nature so extraordinary that nothing can
arrest it; so that it shines, for instance, through
vestments with undiminished fire.
At the same time that it is averred that the car-
$
•
·

SPINEL RUBY AND BALAS RUBY.
117
buncle of the ancients included our oriental ruby, it
is equally certain that this name was applied to all
red stones-oriental ruby, spinel ruby, garnets, &c.
-in the same indiscriminate manner as the East
Indians apply the name ruby to all coloured pre-
cious stones.
When Pegu, that fatherland of rubies, was an-
nexed in 1852 to the English possessions, it was
believed that Europe would receive at least a part
of the rubies that had been for so many centuries
locked up in that country. That hope has been
completely disappointed. It is not even certain
that the mines there continue to be worked. It
would seem also that the regions where rubies exist
are extremely dangerous to approach on account of
lions, tigers, and serpents. To be sure, it is very
probable that merchants in rubies designedly exag-
gerate these dangers to delay competition; but it is
certain that this part of Asia is very little known,
and the known condition of the island of Borneo
seems to justify the opinion.
SPINEL RUBY AND BALAS RUBY.
In connection with the oriental ruby two other
productions of quite a different nature must be
described, namely, the spinel ruby and the balas
ruby.
The first is generally a very vivid poppy red;

118
PRECIOUS STONES.
the second of a violet rose, or a vinegar rose; but
there is no absolute rule for their colour, since Pegu
furnishes white and violet-white spinels; and speci-
mens have been brought from Aker in Sudermania
which are of a bluish gray.
Spinels are brought also from Ceylon and other
oriental countries; everywhere they are found in
the beds of torrents, in the midst of alluvial
deposits.
The primitive form of the crystals of spinel ruby
is octahedral, like that of the diamond; this charac-
teristic suffices to distinguish immediately the spinel
or balas ruby from the oriental ruby, since the
crystals of the latter present the form of six-sided
prisms.
The composition of the spinel ruby and balas
ruby differ essentially from that of the oriental ruby,
the latter being a corundum formed nearly ex-
clusively of alumina, while in the former only 70
parts in 100 are alumina, and the remainder chiefly
magnesia. The colour, moreover, is in part due to
the oxide of chromium, a substance of which the
oriental ruby does not contain the slightest trace.
In a scientific point of view the balas ruby does
not differ from the spinel; and many special works
confound the two completely. But in commerce
the stone called Balas has a value very much below
that of the spinel.

CELEBRATED RUBIES.
119
In the inventory of the crown jewels of France
the price of balas rubies is four or five times less
than that of spinels.
CELEBRATED RUBIES.
The largest ruby known is one mentioned by
Chardin as having been engraved with the name of
Sheik Sephy.
Fig. 54.-King of Persia's Ruby.
Tavernier gives a figure of another celebrated
ruby in the possession of the King of Persia: it is
reproduced in Fig. 54. Its weight was 175 carats.
A third, belonging to the King of Visapur, had
the figure and dimensions of Fig. 55. It was cut,
as will be seen, en cabochon, and it had been bought
in 1653 for nearly $13,866.

120
PRECIOUS STONES.
A fourth, seen by Tavernier in India, is repre-
sented by Fig. 56.
According to the judgment of Tavernier it was
of secondary beauty; yet this celebrated traveller
offered $11,160 to the diamond merchant who pos-
sessed it, but could not obtain it at that price.
A ruby possessed by Gustavus Adolphus, and
presented by him to the Czarina in 1777, at the
Fig. 55.-Ruby of the King of Visapur.
Fig. 56.-Indian Ruby.
time of his journey to St. Petersburg, was the size
of a small hen's egg.
A ruby in the French crown, adorning the order
of the golden fleece, is in the form of a dragon.
Finally, it is seen from the inventory of 1791 that
France then possessed eighty-one oriental rubies,
estimated at $6138.
In England the ruby is especially prized; and
some beautiful and very valuable stones are in the

THE SAPPHIRE.
121
{
hands of the nobility. In America it is less highly
estimated.
ENGRAVING UPON RUBIES.
The ancients seldom engraved the ruby. Pliny
ascribes this fact to the singular reason that seals
made of this stone carried away the wax.
The excessive hardness of the ruby, its costli-
ness, and the great rarity of specimens proper for
engraving are, without doubt, the true reasons which
prevented the ancients from engraving it; the im-
possibility, moreover, of polishing the cavities made
in this substance may have occasioned the fault
which Pliny has ascribed to ruby signets.
In the Odescalchi museum the design of an en-
graved ruby represents Ceres standing with an ear
of corn in her hand.
Another engraved ruby represents a bearded head,
supposed to be that of a Greek philosopher. This
ruby is cut in the shape of a heart, and formed a
part of the collection of the Duke of Orleans.
Both these engraved rubies are spinel rubies.
THE SAPPHIRE.
The word sapphire is derived from the Syriac
saphilah, a name which indicates the same stone in
this Eastern tongue.

122
PRECIOUS STONES.
'
In commerce there are four different stones that
bear the name of sapphire:-
Oriental Sapphire.
Brazilian Sapphire.
Sapphire of Puy.
Water Sapphire.
The three first are corundums, and consequently
true sapphires. The last is a coloured quartz, and
a stone of but trifling value.
The oriental sapphire has been known from
earliest antiquity. It was one of the precious stones
that had place in the breastplate of Aaron. To
the ancients it was the gem of gems, the sacred
stone par excellence. The Greeks dedicated it to
Apollo.
The first sapphires that reached Europe came
from Arabia; later they were imported from Persia.
At the present day they are found principally in
Arabia and the Brazils; and the productions of both
these countries are called oriental sapphires.
There are certain sapphires, generally of a pale
colour, which, when examined under the microscope,
exhibit thread-like shafts directed towards the
faces of the six-sided prism; these threads are pro-
duced by foreign substances, or by vacuities left
among the molecules at the moment of their crys-
tallization. The light reflected upon them forms a
star of six rays, extremely beautiful and remarkable.
Sapphires of this kind are called asteria sapphires,
or star sapphires.

THE SAPPHIRE.
123
The orientals have a deep veneration for the star
sapphire; and M. D'Abbadie, in his travels in
Africa, often commanded the respect of the natives
by allowing a stone of this kind, which he always
carried with him, to exhibit its magical beauty to
their astonished eyes.
It is
A stone of a yellow-green tint, exhibiting a simi-
lar phenomenon, is brought from Ceylon.
called the Cat's Eye. Threads of white asbestos are
inclosed within it, and the light is reflected from
these in an intense manner. When this stone is cut
en cabochon, a white band of light is seen floating in
its interior, that changes position as the gem is
moved before the eye.
The sapphire of Puy is found in the rivulets of
Expilly. Its colour varies from the deepest to the
palest blue; sometimes it passes to a reddish blue,
or even to a yellowish green. Its composition is not
always homogeneous; and the specimens which dis-
play the finest water are those in which the tint
verges upon green. They are found in ferruginous
sand produced by decomposition of basaltic rocks.
Fig. 57 is a view of the mountain of Expilly,
where the sapphires of Puy are found.
Among the celebrated sapphires we must mention
above all that which figured in the famous “affair
of the necklace."
Found in Bengal by a poor man who sold wooden
124
PRECIOUS STONES.
spoons, it was brought to Europe, and bought by
the house of Raspoli at Rome.. Later it became
the property of a German prince, who sold it to
Perret, a Parisian jeweller, for $31,620. This beau-
tiful stone, without blemish or faults of any kind,
weighed 133% carats. It formed afterwards part of
the riches of the Museum of Natural History at
Paris.
This museum possesses another sapphire of ex-
quisite beauty and exceptional size. It is oval, and
measures two inches by one and a half.
A very beautiful star sapphire belongs to one of
the merchant princes of New York; and in England,
among the jewels of Miss Burdett Coutts, are two
magnificent sapphires estimated at $139,500.
In the Hope collection-among several fine spe-
cimens of this gem-is a stone called the "Mar-
vellous Sapphire," which is blue by day and ame-
thystine at night. This gem is said to have afforded
the foundation of one of Madame de Genlis' stories.
ENGRAVED SAPPHIRES.
The ancients engraved the sapphire notwith-
standing its extreme hardness.
There is a beautiful sapphire among the crown
jewels of Russia representing a female figure en-
veloped in drapery. The stone is of two tints, and
1

Fig. 57.-View of the Mountain of Expilly, Central France,

THE TOPAZ.
127
the artist has skilfully used the dark tint for the
woman and the light tint for the drapery. This
gem formed part of the collection of the Duke of
Orleans.
The cabinet of France possesses in sapphire a
very remarkable intaglio representing the Emperor
Pertinax.
The marvel of this kind is an engraving by
Cneïus representing the profile of a young Hercules.
It is in the Strozzi Cabinet at Rome.
THE TOPAZ.
1
The topaz, like its kindred precious stones, is
divided into the occidental and the oriental.
The oriental topaz should be in every respect
carefully distinguished, because it is the only variety
which is composed of alumina nearly pure. The
others contain no more than 57 or 58 parts to 100
of this substance.
The topaz of the moderns is the chrysolite of
the ancients. It is a corundum coloured by a
slight quantity of the oxide of iron to a beautiful
golden yellow. The topaz was originally found, as
Pliny informs us, upon an island in the Red Sea,
which, being often surrounded by fog, was so diffi-
cult to find that the mariners named it Topaza (Gr.
topazein, to guess).

128
PRECIOUS STONES.
This stone is now very rare; and when to the
fineness of its quality it joins a soft clear colour
with a satin-like lustre, it acquires a considerable
value. But the topaz, however perfect, never
reaches the price of a ruby or a sapphire, or even a
fine emerald of equal dimensions.
Occidental Topaz.-Stones thus designated are
not corundums. They are of a more complex com-
position; and the analysis of specimens brought
from different localities proves that occidental
topazes are not identical. They have for a long
time been divided into four varieties:-
Brazilian Topaz.
Saxon Topaz.
Mexican Topaz.
Siberian Topaz.
It should be remarked, however, that while the
proportions of the elements differ in each of these
varieties, their nature is the same. The occidental
topaz is in all cases formed of alumina, silica, and
fluoric acid. The presence of this last substance,
found in no other precious stone, characterizes per-
fectly the genus topaz in respect to chemical
composition.
The primitive type of crystals of topaz is the
right rhomboidal prism (Fig. 58).
Certain modifications occur in the form of these
crystals, which, joined to their colour, enable a
person to decide as to which of the varieties any
topaz in question belongs.

THE TOPAZ.
129
The Saxon topaz generally occurs in the form of
a rhomboidal prism with a base; and its colour
varies from an orange yellow to a straw yellow.
Fig. 58.-Type of Crystal of Topaz.
The Brazilian topaz exhibits most frequently a
rhomboidal prism surmounted by a four-faced pyra-
Fig. 59.-Saxon Topaz.
Fig. 60.-Brazilian Topaz.
mid, and its colour includes all the shades from
orange yellow to wine yellow.
9

130
PRECIOUS STONES.
The Siberian topaz is nearly always found in
rhomboidal prisms, terminated by a ditetragonal
pyramid; it is of a pale blue or green cast of colour,
and sometimes occurs colourless, when it is much
prized. Although in form of crystallization these
Siberian minerals are really topazes, they approach
very nearly by their tint and transparency to the
aquamarine.
Fig. 61.-Siberian Topaz.
Fig. 62.-Topaz of the Grand Mogul.
It
A finely polished topaz belonging to the Grand
Mogul was purchased at Goa for $50,500.
weighed 1574 carats, and was cut in the form
represented by Fig. 62.
ENGRAVING UPON THE TOPAZ.
It was for a long time believed that the ancients
never engraved this gem; but Caire mentions a
THE AMETHYST.
131
topaz which he had had in his own possession
weighing 29 carats, and engraved in Arabic
with the motto, "No one accomplishes but God."
It was probably an amulet, such as are worn by
orientals of the present day, and which are called
by the Arabs gri-gri.
Another celebrated engraved topaz represents
Philip II. and Don Carlos. It is a white topaz, en-
graved by Jacopo da Trezzo.
The house of Orleans had a very beautiful octa-
gonal topaz engraved with a Mercury; and in
Turin, in the Generosio collection, was a celebrated
topaz intaglio, representing Victory enthroned in a
chariot.
THE AMETHYST.
The oriental amethyst is a rare substance of
magnificent lustre, and of a violet colour slightly
tinted with red.
The amethyst was the ninth stone in the breast-
plate of Aaron; and in modern times it is the
sacred stone which ornaments the cross and the
pastoral ring of Catholic bishops.
In the inventory of the crown jewels of France,
1791, three superb oriental amethysts are mentioned,
one of which weighed 13 carats, and was valued
at $1116.
But the greater part of the amethysts of commerce
132
PRECIOUS STONES.
are occidental amethysts. As their composition
and value have nothing in common with the oriental
amethyst they will be described elsewhere.
ENGRAVING UPON THE AMETHYST.
Ancient engravings upon amethyst are numerous.
That which has been chosen as an example (Fig.
63) represents Antonia, the daughter of Mark
Antony, and the wife of Drusus, a beautiful

Fig. 63.-Antonia, wife of Drusus.
princess, who, to use the touching language of
Lenormant, "embodied in herself all the glory and
the sorrow of her time." She is represented as the
goddess Ceres, and carries a horn of plenty. In
the National Library of France there is a mag-
nificent work in amethyst, a profile (supposed to be
Maecenas at an advanced age) engraved by Dios-
corides, one of the four celebrated engravers
mentioned by Pliny.

EMERALD, BERYL, AQUAMARINE.
133
Among the finest gems of the Pulsky col-
lection is the head of a Syrian king upon a pale
tinted amethyst, engraved with the artist's name
ΝΕΑΡΚΗΣ
EMERALD, BERYL, AQUAMARINE.
These three substances are, in a scientific point
of view, very nearly identical; but in commerce the
value of the emerald is infinitely greater than that
of the beryl and aquamarine.
The emerald, when it possesses a green tint of a
beautiful quality, and when it is entirely hyaline, is
one of the most rare and precious of gems. On
the contrary, when it appears in semi-transparent
crystals of a watery green, it is quite common;
indeed there are few granitic mountains where it
has not been observed.
The colour so remarkable in the emerald is
due to a pretty large quantity, 8 to 9 parts in 100,
of oxide of chromium.
The fundamental form of crystals of emerald is
the regular six-sided prism. As the side of the
base nearly always equals the height, the faces of
emerald crystals vary very little from a square.
Another form which frequently occurs is the
twelve-sided prism, which is derived directly from
the primitive form by the modification of the six
vertical edges.

134
PRECIOUS STONES.
Like the other corundums the emerald is formed
chiefly of alumina, but it has a peculiarity which
renders it interesting to the chemist, since it con-
tains a considerable proportion, 12 to 15 parts in
100, of a rare body, glucina, the discovery of which
is due to the illustrious chemist Vauquelin.
It was for a long time believed that emeralds
were always found in connection with granitic rocks;
Fig. 64. Fundamental Form of
Emerald Crystals.
Fig. 65. Very common Form of
Emerald Crystals.
but in 1848 M. Léwy, in the course of his travels in
New Grenada, discovered that this opinion was
erroneous.
M. Léwy has shown in fact that the most beauti-
ful specimens, those of the mine of Mouza, so far
from existing in crystalline rocks, exist, on the con-
trary, in the best defined secondary formations-in
that division of the cretaceous formation to which

BERYL AND AQUAMARINE.
135
geologists have given the name of the neocomian.
The fossils brought home by M. Léwy leave no
room for doubt on this subject.
Since the publication of the discovery of M. Léwy,
MM. Nicaize and Montigny have found in the
valley of the Harrach, in the province of Con-
stantine (Algeria), a bed of emeralds, appertaining,
like that of America, to the cretaceous formation.
BERYL AND AQUAMARINE.
The beryl and the aquamarine have the general
composition and constitution of the emerald; but
they differ from it in the absence of the oxide of
chromium, which is in them replaced by the oxide
of iron. The colour remains the same, but it is
much feebler and less pure than in true emeralds.
Beryl.-Among lapidaries and dealers in precious
stones the beryl and the aquamarine constitute a
well-defined group, altogether distinct from the
emerald. With them the beryl is the oriental
species of this group, and the aquamarine the
occidental.
For a long time the beryl was only known in
India; afterwards it was met with in Arabia; and
still later remarkable fragments of it were found in
Russia, at Beresof, and in the environs of Lake
Bolchoi.

136
PRECIOUS STONES.
Aquamarine.-The aquamarine is a stone of but
trifling value, and yet it possesses a quality which
should have prevented it from falling into its present
low estimate; it does not lose its brilliancy in arti-
ficial lights.
“It is a curious spectacle," says Babinet, "to see
a magnificent blue sapphire lose in the night all its
glories, when a poor trinket of aquamarine not only
retains all its effect, but even seems to gain brilliancy.
The English are as fond of the aquamarine as the
Spanish are of the topaz.'
""
The greater part of the aquamarines of commerce
are furnished by Brazil. They are brought to
Europe completely cut, and are sold by weight, but
with extreme variations, since large and beautiful
specimens are valued at from $75 to $95 the ounce,
while the small ones hardly bring $5.
Formerly the aquamarine was very abundant in
Daouria, upon the frontiers of China, whence the
Russian merchants took them in exchange for furs.
They are now found in Siberia, the Ural Mountains,
the Altai Mountains, &c.
The emerald, so highly esteemed in our day, was
not less valued by the ancients. Pliny describes it
in the following terms:-
"There is no colour so pleasing to the eye as that
of the emerald. Whoever delights in the verdure
of herb and leaf must enjoy infinitely more the con-

BERYL AND AQUAMARINE.
137
templation of emeralds, for no verdure can compare
to theirs. They are the only stones that charm the
eye without wearying it. Even when the eyes are
fatigued by having looked too continuously on
anything, the sight of an emerald soothes and
strengthens them. Lapidaries can find nothing
more refreshing for their tired eyes than the soft
greenness of this stone. It loses its lustre neither
in sun nor in shade, nor in artificial lights. It
shines continually with the same soft glow."
The emerald is mentioned several times in our
translation of the Bible, but it is not certain that
the word so translated really meant our emerald.
Among precious stones there is not one that has
formed the basis of such great exaggerations as the
emerald.
It is Herodotus who first describes those gigantic
emeralds of which Theophrastus, Appian, and Pliny
make later mention.
Theophrastus relates that in the books of the
Egyptians it was stated that a king of Babylon had
sent to one of their kings an emerald four cubits
long and three thick; and that there was in Egypt,
in a temple of Jupiter, an obelisk made of four
emeralds, which nevertheless was forty cubits long,
four cubits thick at some places, and two in others.
He adds, also, that at the time when he wrote, there
was yet to be seen at Tyre, in the temple of Her-

138
PRECIOUS STONES.
cules, an upright column, made of a single emerald.
Appian, too, describes a colossal statue of Serapis,
of the height of nine cubits, carved out of a single
emerald.
It is evident that these descriptions do not apply
to our modern emerald. The productions they
refer to were probably jasper and malachite; and,
above all, vitreous masses artificially coloured by
metallic oxides.
REMARKABLE BERYLS AND AQUAMARINES.
The finest beryl known is in the collection of
Mr. Hope. It weighs nearly 6½ ounces, and cost
$2325. It came from the mine of Cangayum, in the
district of Coimbatoor, in the East Indies.
A magnificent beryl surmounts the globe in the
royal crown of England. It is perfectly clear, and
of a lovely colour. It is cut in an oval form, and is
inches long, 1½ in width, and 1 in depth.
2
A celebrated aquamarine adorned the tiara of
Pope Julius II. It measured 2 inches in length,
and 2 in thickness. Notwithstanding a slight
flaw, it was considered by amateurs a very remark-
able gem.
. Caire mentions an aquamarine which he had
seen in London that weighed when cut 250 carats,
and was valued by its possessor at $465.

ENGRAVING UPON AQUAMARINE.
139
In 1827, in the town of Mouzinskaïa in Russia, a
superb specimen of aquamarine was found, valued,
we are seriously told by the Russians, at $111,600.
ENGRAVING UPON AQUAMARINE.
A considerable number of both modern and
ancient engravings are executed upon this stone.
The gem represented in Fig. 66 is a part of the
Fig. 66. Julia, daughter of Titus.
collection of the National Library of France. It is
the head of Julia, the daughter of Titus, and is
signed by the artist Evodus. It was mounted ori-
ginally with sapphires and pearls, and formed part
of the decorations of a reliquary belonging to the
abbey of St. Denis.

140
PRECIOUS STONES.
ENGRAVING UPON THE EMERALD.
The brittle texture of the emerald prevented it
from being a favourite with engravers, consequently
there are few engraved emeralds.
There is a description of a beautiful composition
executed in the middle ages upon this stone. It
represented the soul led away by the pleasures.
CYMOPHANE.
The cymophane is formed like the emerald, of
alumina and glucina.
The cymophane of modern mineralogists is the
oriental chrysolite, the chrysopal, and the chryso-
beryl of the lapidaries. It is remarkable for its
lively brilliancy, its polish, similar to that of the
sapphire, and its warm gay tint. But its celebrity
arises from its unique property of displaying blue
reflections, with a milky tint that seems floating in
its interior. This circumstance originated the
name given to it by Haüy, which signifies floating
light.
Crystals of cymophane are usually found in
alluvial soils; in Ceylon and Brazil they occur in
the same sands that furnish crystals of topaz, corun-
dum, &c.-sands formed by the disintegration of
ancient rocks. Fine specimens of cymophane have

THE TURQUOISE.
141
recently been found in Connecticut and in the Ural
Mountains.
THE TURQUOISE.
There are two species of oriental turquoise, the
old rock and the new rock; and there is also an
occidental turquoise.
The terms old rock and new rock were applied to
the turquoise in Persia. "The mine of turquoise,"
says Tavernier, "which furnishes the most beauti-
ful stones, is three days' journey from Meshed,
turning to the north-west after passing the large
town of Nishabourg; it is the old rock. The other,
which is five days' journey, was discovered and
worked more recently; it furnishes turquoises of a
whitish blue, and almost valueless; it is the new
rock."
When Tavernier travelled in the East the King
of Persia had already for a long time reserved for
himself all the products of the old rock. He had
ornaments made of them, which he presented to
princes and kings.
When the embassy was sent by the King of
Persia to Louis XIV., among the many rich presents
conveyed to the French monarch were a large
quantity of turquoises. But all those who saw
them were unanimous in deciding that they were
noways remarkable, and by no means answered the

142
PRECIOUS STONES.
idea that had prevailed in Europe, of the much
vaunted turquoises of the old rock. Perhaps the
mine was already more or less exhausted.
Oriental Turquoise. This is another aluminous
stone; but alumina forms hardly more than half of
its composition.
The blue colour, so characteristic of the turquoise,
is due, in great part at least, to a combination of
phosphoric acid, copper, and iron, and probably also
to water, of which it contains 18 or 19 parts in 100.
The turquoise harmonizes well with diamonds
and pearls, and is frequently employed in jewelry.
It is consequently an object of some commercial
consideration; but as it is pretty abundant it does
not reach a high price, unless in specimens of a
very unusual size.
At the sale of M. Drée's cabinet, a turquoise of
the old rock, measuring 47 inch by 43 inch, was
sold for $93; and as an example of the wide dif-
ference between the turquoises of the old and the
new rock, there was sold at the same sale, for
$22.50, a turquoise of the new rock, 39 inch by
*37 inch, of the most beautiful sky-blue tint.
The turquoise is the stone that the orientals
employ most frequently for amulets. Sentences
are frequently engraved upon them, and generally
quoted from the Koran.
Occidental Turquoise.-The occidental turquoise

ENGRAVING UPON THE TURQUOISE.
143
is a substance altogether special in its composition,
and above all in its organic origin.
It is, in point of fact, a fossil ivory, produced
from the teeth of a past race of animals, brought
accidentally in contact with substances containing
copper, and which has absorbed a sufficient quan-
tity of them to colour the entire mass with a
cerulean hue more or less deep.
ENGRAVING UPON THE TURQUOISE.
The low degree of hardness possessed by the
turquoise probably deterred the ancients from often
engraving on this stone, or, it may be, these speci-
mens of antiquity have not been sufficiently durable
to reach our time. In either case, there are very
few engraved turquoises known. Caire, however,
cites a few.
In the Genevosio collection there is an amulet,
convex on one side and flat on the other, showing
upon one side an engraving of a veiled Diana hold-
ing two branches in her hands, upon the other a
sort of sistrum, a star, and a bee: Greek letters are
inscribed upon both faces.
The cabinet of the Duke of Orleans contained
two engraved turquoises; one representing Diana,
with her quiver upon her shoulder; and the other,
the elder Faustina.
A turquoise in the gallery of Florence, nearly as

144
PRECIOUS STONES.
large as a small billiard ball, is engraved with a
head which is possibly that of Cæsar, but more
probably of Tiberius.
The group which we have just examined compre-
hends a certain number of precious stones that may
be easily confounded with each other, or with cer-
tain other gems of which we have yet to speak.
As will be seen from the table at the end of the
book, in which are briefly stated the general charac-
ters of precious stones, it is almost always possible
to distinguish with tolerable facility those that at
first sight might be confounded.
Thus, the transparent and colourless corundum
resembles.the diamond, the aquamarine, the colour-
less spinel, and the quartz.
Now the corundum has double refraction, and
the diamond simple refraction; accordingly nothing
else is necessary than to look at the flame of a
candle through the doubtful stone, in the manner
pointed out in Chapter i.
The specific gravity of the corundum-3′9—
enables us to distinguish it at once from quartz, of
which the specific gravity is only 2·65, and from the
emerald, which has a specific gravity of about 2·67.
The white spinel, which, like the diamond, possesses
simple refraction, will be distinguished from the
corundum by the same optical test.

METHODS OF DISTINCTION.
145
The red-coloured corundum may be confounded
with the red spinel, the red tourmaline, and the
burnt topaz.
The optical distinction applicable to the colour-
less spinel is equally so to the coloured spinel.
The tourmaline and burnt topaz, again, may be
easily distinguished from the corundum by their
specific gravities alone-that of the tourmaline
being 3'07, that of the topaz 2·65.
The oriental sapphire may be mistaken for the
water sapphire or the blue emerald; the green
corundum for the emerald of Bogota; the yellow
corundum for the yellow topaz, the yellow quartz,
the cymophane, and the zircon. The occidental
amethyst, lastly, may be confounded with the
oriental amethyst.
In all these cases the specific gravities are often
sufficient, and when employed in conjunction with
the other characters indicated in the general table
they always enable us to decide with certainty.
10

PART V.
Quartz. Occidental Topaz. Smoky Topaz, or Alençon Diamond.
Water Sapphire. False Emerald. Bohemian or Brazilian Ruby.
Hyacinthe of Compostella. Iris. Aventurine. Opal. Hydrophane.
Agate. Chalcedony. Chrysoprase. Cacholong. Heliotrope. Onyx.
Sard. Sardonyx. Sardoine. Sardagate. Jasper.
Zircon.
lazuli.
Garnets. Peridot. Olivine. Fade. Tourmaline. Lapis-
Malachite. Hematite.
"Some seek amidst the pebbles of the stream
The verdant beryl, or the diamond's gleam,
Or where the bright green jasper meets their view,
Or the clear topaz shows its lighter hue,
Or the sweet amethyst which, serenely bright,
Diffuses far and wide its tranquil light."
The stones of which we are now about to speak fall
naturally into two classes, the first composed almost
exclusively of silica, the second having a com-
position more complex. The latter class contain a
considerable proportion of silica also, but it is
always combined with one or more substances, the
nature of which varies in every stone.
FIRST CLASS.
The stones comprised in this class may be
7
"7
•

QUARTZ.
147
arranged, from an artistic point of view, into three
very distinct sections.
The first includes all the stones formed of pure
silica crystallized.
The second comprehends all the stones formed of
pure silica not crystallized.
The third includes the stones formed of silica,
always nearly pure, but containing some traces of
colouring substances, which, however insignificant
their quantity, communicate, in a commercial and
artistic sense, a value to the stones that is alto-
gether special.
In the first group are placed quartz or rock cry-
stal, and all its varieties. The latter bear very
different names in commerce, but their composition
is almost identically the same. If a piece of white
silk were cut into shreds, and each of these pieces
plunged into a dye of different tint and intensity,
a different name might easily be given to each
fragment according to its colour; but its substance
would still be the same. Quartz holds the same
relation to the precious stones of the section we
are about to consider, as the white silk would bear
to the tinted morsels we have described.
FIRST SECTION.
QUARTZ.
Quartz, which is called also rock crystal, is one of

148
PRECIOUS STONES.
the substances most frequently occurring upon the
surface of the earth, and probably also in its interior.
"It forms," says an English writer, "about one-
third of the mass of those immovable hills whose
summits pierce the clouds, and nearly the whole of
the mobile soil of the trackless desert rolling with
the wind like the waves of the sea."
Fig. 67.-Primitive form of Quartz.
Fig. 68. Most ordinary form of
Quartz Crystals.
Crystals of quartz do not often occur of dimen-
sions sufficiently great to attract the eyes of the
common observer. Some magnificent specimens,
however, are found in the ancient formations, which,
as we have mentioned, are formed principally of
silica: here indeed we would naturally look for
them; but that which would seem much less pro-
bable, and yet actually occurs, is the presence of

QUARTZ.
149
magnificent crystals of quartz, of an absolute purity,
in the midst of rocks nearly exempt from all trace
of silica; in Carrara marble, for example, and in
certain gypseous formations in the south of France.
Quartz is formed by the union of two bodies;
the one, silicon, is a substance analogous to carbon;
Figs. 69 and 70.-Modified Crystals of Quartz.
the other, oxygen, is a gas, and one of the principal
constituents of atmospheric air.
The primitive form of quartz is the rhombohedron,
but the primitive crystals are extremely rare. The
most common form is the regular hexagonal prism
terminated with six-sided pyramids (Fig. 68).
It is rare for the terminal pyramids to have all
the faces equal. Ordinarily, on the contrary, three
of these faces are developed at the expense of the

150
PRECIOUS STONES.
other three, and thus we have the crystal repre-
sented by Fig. 69.
In other cases the crystals are not terminated by
pyramids, but by ridges, as in Fig. 70. In this
case the form of the crystals is greatly altered, and
the regularity, to a certain extent, disappears.
If in the regular crystal (Fig. 68) we suppose the
prismatic part to be diminished little by little with-
out the form being otherwise changed, then, when
Fig. 71.-Dodecahedral Quartz.
the prismatic portion is quite removed, and the
pyramids are applied base to base, the crystal re-
presented by Fig. 71 is obtained. It is a dode-
cahedron, all of whose faces are equal, and bounded
by isosceles triangles.
Crystals of this form occur in the midst of the
gypsum which accompanies the ophites of the Pyre-
nees. Numerous examples of perfect purity occur
also in the gypsum beds of Provence, which belong
to the trias formation.

QUARTZ.
151
Crystals do not ordinarily attain large dimen-
sions. For the greater number of minerals, crystals
of 2 inches are almost gigantic: few indeed ex-
ceed 4 inches in height. Quartz, however, forms
an exception to this rule. Specimens are brought
from Madagascar more than 12 inches in length,
and remarkably pure and transparent, notwith-
standing their great size. The rock crystal of this
island is used for the object-glasses of astronomical
telescopes. Magnificent crystals have also been
found in the Alps; one of these Alpine crystals,
taken in Italy by the French, was borne in triumph
to Paris in 1797. There is a beautiful specimen
in the Museum of Natural History at Paris which
measures 3 feet every way, and weighs nearly 800
pounds. It was found at Fischbach in the Valais.
At the French Exhibition of 1866, in the sections
of Japan and of Brazil, there were some wonderful
crystals. One crystal brought from Brazil weighs
212 pounds, is 2½ feet high, and I foot in diameter,
and is a perfect six-sided prism.
A remarkable phenomenon in quartz is exhibited
by the fluid drops which are contained in many
specimens. Sir David Brewster ascertained that
the fluid is not water, but of an oleaginous
nature, one part volatile at twenty-seven degrees,
and the other a fixed oil. Prof. Dana has named
the former cryptoline, and the latter brewsterine.

152
PRECIOUS STONES.
?
Some beautiful specimens of quartz crystals, beaded
with these imprisoned drops, have been found at
Trenton Falls, in the state of New York.
EMPLOYMENT OF QUARTZ IN THE FINE ARTS.
Quartz has but little value of its own; but when
it is made into vases, cups, and other artistic ob-
jects, it acquires a high price.
One
The Athenians produced some exquisite works
of art in rock crystal, and the Romans valued it
very highly in the form of vases. Nero had two
cups of it, which he broke in his rage when he
heard of the revolt that caused his downfall.
of these cups was estimated at over $1900.
The élégantes of Rome were in the habit of
using balls of rock crystal to cool their hands, and
certain occult charms were also said to reside in
these cold smooth globes.
In the middle ages the Venetians produced some
beautiful objects in rock crystal; and Milan has
long been famous for its statuettes, vases, and
girandoles of this material. But desire of gain has
deteriorated the artistic value of these productions;
cut crystals have come to be sold by weight, and
the cutting is naturally falling into neglect.
In the cathedral at Milan the burial shrine of St.
Charles Borromeo is wholly formed of plates of
COLOURED QUARTZ.
153
rock crystal of 6 or 8 inches square each, set in
a framework of silver. The shrine was the gift
of Philip IV. of Spain, who employed eight years
in collecting the necessary quantity of rock crystal.
COLOURED QUARTZ.
When crystals of quartz are found combined
with certain traces of colouring matter, they con-
stitute distinct species in commerce, and take com-
pletely different names.
Combined with iron and alumina quartz becomes
yellow, and takes the name of the occidental or
Bohemian topaz.
Impregnated with a bituminous substance it be-
comes more or less darkened, and is called the
smoky topaz, or Alençon diamond.
Combined with a slight proportion of oxide of
manganese it takes a beautiful violet colour; it is
then the occidental amethyst.
Coloured blue by iron and alumina, it becomes
the water sapphire.
Coloured rose by iron and manganese, it is the
Bohemian or Brazilian ruby.
Combined with a notable proportion of oxide of
iron, it becomes a brown red, and constitutes the
hyacinth of Compostella.
But among all these varieties there are only two

154
PRECIOUS STONES.
that are really valuable-the amethyst and the
water sapphire.
OCCIDENTAL AMETHYST.
The amethyst, whose violet colour varies accord-
ing to the quantity of oxide of manganese com-
bined with the silica, has all the properties of
quartz.
This substance is found in France, Prussia, Hun-
gary, Arabia, Ceylon, Kamtschatka, &c. The en-
virons of Carthagena in Spain furnish the most
beautiful specimens of amethyst; and they are the
more remarkable that they show a purple reflection
vying with that of the oriental amethyst.
Brazil furnishes to commerce at the present day
the greater number of amethysts. In that part of
the world amethysts attain an enormous size. A
block of amethyst, sent from the Brazils to Calcutta,
is said to have weighed 98 pounds. Some of the
Brazilian specimens are of two colours. The Count
de Bournon possessed a cut and polished stone of
this kind half violet and half yellow.
The ancients believed that wine, when drunk
from an amethyst cup, lost the power of causing
intoxication. Accordingly the attributes of Bacchus
and Silenus are frequently found engraved upon
ancient cups of amethyst.

WATER SAPPHIRE.
155
WATER SAPPHIRE.
The water sapphire has nothing in common but
the colour with the oriental sapphire; and even its
colour-a clear white mixed with sky-blue-ex-
hibits to the most inexperienced eyes a shade
completely different from the magnificent velvety
blue of the oriental sapphire.
There are water sapphires composed of nearly
pure quartz; but those brought from Ceylon are of
a much more complex composition. Somewhat
more than half their weight is silica; the rest is a
combination of alumina, magnesia, oxide of iron,
and oxide of manganese. This variety is called
dichroite, on account of its curious property of
showing two very dissimilar colours when viewed
from different sides-a beautiful blue in the direction
of the axis, and a yellow gray in a direction perpen-
dicular to this line.
IRIS.
Although this stone is no longer mounted by
jewellers, and is only seen in antique jewels, it
must not be passed over in silence; both because it
was held at one time in high repute, and because it
is liable to be confounded with several precious
stones, particularly the opal.
The iris is a very limpid and very transparent

156
PRECIOUS STONES.
;
quartz. It is crystallized, a fact which immediately
distinguishes it from the opal.
Under the influence of the light the iris is
illumined with all the tints of the rainbow. This
effect is produced by a great number of flaws and
natural crevices contained in its interior; but its
fires are always much less close than those of the
opal.
Notwithstanding the neglect into which it has
fallen, the iris was once very highly thought of.
Much was said in the time of the First Empire of a
certain parure of iris sometimes worn by the Em-
press Josephine. It is described among regal
jewels in the Lapidarium of Marbodus:
"By the Red Sea the swarthy Arabs glean
The iris, splendent with the crystal's sheen;
Its form six-sided, full of heaven's own light,
Has justly gained the name of rainbow bright."
THE AVENTURINE.
The aventurine is a quartz of a clear brown or
reddish-white colour, sprinkled with little spangles
of yellow mica, that glitter like gold. It has been
found also with a ground colour of yellow, of light
gray, and of greenish-white.
The yellow variety has been called sunstone. It
is very scarce, and exceedingly beautiful.
All aventurines do not owe their reflections and
glitter to particles of mica. There is a kind—and

THE AVENTURINE.
157
that too pre-eminently esteemed-in which effects
of this kind are produced by the presence of little
crystals of quartz scattered through the mass, and
reflecting the light on all sides. This last variety
has generally a very clear tint of greenish-white, or
sometimes of a reddish-brown.
The aventurine with mica was formerly brought
from the borders of the White Sea; but at present
it is furnished by Silesia, Bohemia, Siberia, and
France. The species with crystals comes from
Spain, and has for some years been produced by
Scotland also.
Many substances are sold in commerce under the
name of aventurine that produce similar effects, but
are quite different in composition, particularly cer-
tain varieties of felspar, filled with flaws and minute
fissures.
SECOND SECTION.
Before commencing the study of the stones com-
prised in this section, it is necessary to make an
important remark.
So far the stones that we have examined are
crystallized, and nearly always anhydrous. It is
quite otherwise with those that are to be described
in this group. They show no indication of crys-
tallization, and nearly always contain water.
It is probable that their elements have never
F
...

158
PRECIOUS STONES.
been either melted by the direct action of heat, or
deposited by the evaporation of a dissolving liquid.
Everything, on the contrary, leads to the belief
that they existed primitively in a gelatinous mass
suspended in water.
Certain results produced by one of the grand
Fig. 72.-The Great Geyser (Opals and Chalcedonies).
natural phenomena of our own time sustain this
opinion.
The boiling waters of the Iceland geysers-that
at irregular intervals are projected upwards some-
times to the height of fifty yards into the air-are
heavily charged with silica; and this substance, de-

THE OPAL.
159
posited little by little, produces at last enormous
piles.
In these silicious masses are found branches of the
birch-tree completely silicified, and in the midst of
a reddish clay a thin layer of chalcedony, which, so
long as it remains watery, is translucid, but when
dry becomes opaque and like white enamel.
In these same deposits of the geysers small
portions of silica are found, which perfectly resemble
the noble opal so long as they remain hydrated;
but they lose their vivid colours when they are
dried.
M. Descloizeaux is disposed to conclude from
this observation that opals and chalcedonies found
in volcanic earths had their origin in phenomena
analogous to those of the Iceland geysers.
THE OPAL.
The opal is formed of silica like the stones of
the first group; but it differs from them by the con-
stant presence in its composition of a certain quan-
tity of water, making 5 to 12 parts in 100 of its
weight. M. Damour has shown, moreover, that
when sulphuric acid is applied to the opal the stone
turns black, leading to the conclusion that it con-
tains organic matter, probably bituminous. This
the sulphuric acid would seem to destroy by setting
its carbon at liberty.
31

160
PRECIOUS STONES.
The opal has no colour that may be called its
own, but a faint bluish tinge analogous to the tint
of certain resinous quartz, of which it is a variety.
Its true beauty and its great value are produced
by a physical accident; it is traversed by a multi-
tude of fissures filled with air and moisture, which
reflect all the prismatic colours. The tender violet
of the amethyst, the blue of the sapphire, the green
of the emerald, the golden yellow of the topaz, and
the flashing red of the ruby, appear at times isolated
in certain parts of the stone, at times crossing each
other in vivid play with an effect that is magical.
The opal is found in Arabia, Ceylon, Hungary,
Saxony, Ireland, Iceland, Scotland, and Mexico.
Hungary and Mexico furnish the greater number
to commerce; and some beautiful specimens have
been recently brought from Honduras. The stones
from all these places are true opals. Connoisseurs
can usually distinguish the precise locality from
which they are derived at a glance.
The opal occurs in veins or gangues in ancient
formations, and is not scarce; but the parts that,
after cutting, will display all the storied fire of the
opal are very rare.
Beginning at the resinite quartz without fissures,
and consequently without fire, and choosing suc-
cessively fragments more and more closely fissured
until the maximum is reached of the effect of light,

THE OPAL.
161
an endless series of opals is obtained; but in com-
merce only three varieties are recognized-
The Oriental Opal.
The Fire Opal.
The Common Opal.
The oriental opal, called also the noble opal and
the harlequin opal, shows generally in its fire a tri-
angular disposition very characteristic. It exhibits
flashes or flames of the most brilliant colours.
The affection that the ancients entertained for
this beautiful gem was unbounded. The Roman
senator Nonnius preferred exile to parting with a
brilliant opal the size of a filbert, which Mark
Antony coveted.
A very beautiful opal, considered by the virtuosi
of Vienna and Dresden as the third in rank of the
beautiful opals of the world, is described by Jack-
Fig. 73.-Opal of D'Augny.
son as having three longitudinal bands of the harle-
quin kind, from the uppermost of which rose perpen-
dicularly the most resplendent flames. It measured
11
162
PRECIOUS STONES.
nine lines by six. In the last century the two most
famous opals belonged, one, round and very brilliant,
to the amateur Fleury; the other, fascinatingly
vivid-an oval of the dimensions of Fig. 73-to the
distinguished financier D'Augny.
The fire opal is furnished principally by Mexico.
Its colour, more pronounced than that of the orien-
tal opal, and the carmine or vinous red tint of its
fires, permits it to be easily recognized. At its
maximum of effect the fire opal is brilliantly lovely;
but its beauty is easily deteriorated by atmospheric
influence.
The common opal displays very little fire; its
colour is milk-white, which, joined to a texture ex-
tremely homogeneous, renders it semi-transparent.
It is said that since the opal was introduced by
Sir Walter Scott into his novel of Anne of Geierstein,
its favour has sensibly declined; and the gem, con-
sidered by the ancients to exercise the combined
virtues of the amethyst, ruby, and emerald, is
branded now as "an unlucky stone."
ENGRAVING UPON THE OPAL.
The work of engraving upon the opal is very
difficult, and often quite impossible, on account of
the thousand fissures of the stone. Besides, the
fine effects of light which give it special value are

THE HYDROPHANE.
163
only attainable in the maximum degree by simple
polish.
An antique engraving upon a presumable opal
is a head of Sappho; and in the collection of the
Duke of Orleans was a head of Juba engraved upon
an opal. There is, too, in the national collection
at Paris, an opal engraved with a portrait of
Louis XII.
THE HYDROPHANE.
The hydrophane, composed of 93 in 100 parts of
silica, 2 of alumina, and 5 of water, is a very cele-
brated stone, known from early antiquity.
In its ordinary state the hydrophane is a white
or reddish-yellow substance, feebly translucent or
completely opaque. But if it is plunged into water
it disengages little bubbles of gas, and at the same
time becomes transparent, and sometimes displays
the colours of the opal.
Taken from the water this curious stone keeps its
transparency for a short time, but gradually as the
water evaporates becomes once more opaque.
The ancient mineralogists, considering this stone
an unexampled marvel, gave it the name of Oculus
Mundi, the "eye of the world.”
164
PRECIOUS STONES.
THIRD SECTION.
AGATE.
The agate, unlike other precious stones, very
rarely occurs in veins; it is almost always in the
state of concretions; sometimes in the form of
geodes or balls. Occasionally there is found in the
side of one of these balls a sort of funnel through
which the silicious matter was introduced.
Sometimes the gelatinous silica has been abun-
dant enough to give rise to homogeneous deposits
of a certain depth; the stone in that case is of uni-
form colour; but often the deposits are in very thin
layers, and of different shades of colour; often, too,
they are moulded by the cavities of the body which
forms their support, and take from its irregularities
all sorts of dispositions with very variable shadings.
In cutting a section across a stone of this cate-
gory, extremely different effects are obtained by
following different directions. The varied zones
and colours of the stone produce, too, infinite
varieties; and descriptive names have been be-
stowed upon agates, according to these changes, as
rainbow, cloud, moss, star, ruin, landscape, fortifi-
cation agate, &c. The differences between all these
varieties are extremely slight in a physical or
chemical point of view.

AGATES.
165
Agates are divided naturally into two varieties:-
Agates of a single tint.
Agates of several tints.
FIRST VARIETY.
Chalcedony.-The chalcedony is quite a common
stone, of a dull or milky-white; and sometimes of a
bluish tint, when it is called saphirine.
The ancients obtained chalcedony from Egypt
and Syria, and it was an object of considerable
commerce at Carthage. It probably derived its
modern designation from Karchēdōn, the Greek
name for Carthage. It is found in England, Ire-
land, Germany, Italy, &c.
Chrysoprase.—Chalcedony coloured by the oxide
of nickel, varying in colour from deep verdigris to
the palest green. It takes a very beautiful polish,
and fifty years ago was fashionable in jewelry,
though now quite forgotten.
Cacholong.—A variety of chalcedony of a whitish
tint, cloudy almost to opacity. It is found in
Bokhara, Ireland, Greenland, and the Faroe
Islands.
Cornelian.-A species of chalcedony, but of a
finer grain. The ancients confounded it with the
sardoine, and it was not until the thirteenth century,
in the writings of Albertus Magnus, that the dis-
tinction became established.

166
PRECIOUS STONES.
The cornelian has sometimes the colour of
polished horn; there is one variety that resembles
the hyacinth, and another, of vermilion red, some-
what analogous to the ruby. Its colouring is due
to the oxide of iron, and in certain varieties to
organic matter, clearly discernible by analysis.
Heliotrope.-A translucid agate of a lively leek-
green colour, spotted with red. The ancients used
it, as Pliny tells us, for looking at eclipses of the
sun, as we use smoked or stained glass; and it was
said also to change the colours of the sun's rays
into blood-red, when it was plunged into a vase of
Hence the name heliotrope, from the Greek
water.
helios, the sun; and trepo, to turn.
SECOND VARIETY.
Onyx.—The onyx is the most celebrated variety
of all the variously tinted agates.
Originally the name onyx was given to agates
which had the appearance of a nail (Greek, onyx)
where it joins the flesh; but it is now used for
stones which exhibit marked contrasts of colour in
bands, as black and white, or black and whitish-
gray.
When an onyx unites in a desirable degree these
conditions, it constitutes a stone of value, on
account of the resources offered by it to the en-
graver, through the contrast of colours.
JASPER.
167
Sard. This word, very anciently used, is said by
Braunius to be derived from the Hebrew sered, "a
red colour." However this may be, it is to agates
of this colour that the name is applied.
Sardonyx.-A stone formed, as its name implies,
of the sard and the onyx, using the latter term in
its primitive signification. The sardonyx is a
stone displaying alternate layers successively
whitish and carnation red.
Sardoine. Considered by many mineralogists as
identical with sardonyx. Engravers, however, re-
cognize between these two stones a marked differ-
ence: for them, the sardoine is an agate whose deep
colour partakes both of yellow and red without
either colour predominating. In colour, therefore,
the sardoine differs completely from the sardonyx.
Sard-agate.-A semi-transparent stone formed of
an inferior layer of orange-red or pale yellowish-
red, and a superior layer of whitish tint, disposed
one upon another with perfect regularity.
JASPER.
The precious jasper is the jaspeh of Aaron's
breastplate; the iaspis of the Greeks.
"The property which distinguishes jasper from
other varieties of quartz is its complete opacity even
in thin flakes. Jasper is often a silex that has
168
PRECIOUS STONES.
become opaque either by alteration that it has
undergone, or by the addition of a certain quantity
of oxide of iron, or of hydrate of the same oxide.
There are red jaspers, brown jaspers, and green jas-
pers. In certain circumstances, as in the Egyptian
pebble, the jasper presents irregular zones, which
display a structure roughly concentric" (Du-
frénoy).
It is one of the thousand varieties of rocks known
under the name of jaspers. These varieties, hard
enough to cut glass, present wide bands of diverse
colours, generally red and green, upon a brown
ground.
The silicious element predominates in the jas-
pers, but with it is associated certain bases (alumina,
oxide of iron, &c.), sufficient to render the whole
fusible under the flame of the ordinary blowpipe,
which is not the case with quartz or its varieties
that are very nearly pure.
The substances known in commerce under the
name of jaspers differ so greatly from each other
that their price varies from 20c. to $12 the pound.
ENGRAVING UPON AGATE, &C.
It is the agate, and the varieties of which it is the
type, that have in all ages furnished to the engraver
the stones best suited to his art.

ENGRAVING UPON AGATE.
169
One of the most remarkable engravings upon
agate, and one of the finest specimens of this stone,
is represented by Fig. 74. It is the bust of Alex-
ander the Great. The head is carved in relief, and
P. Sellen, dal
Parmes
Fig. 74.-Agate, Alexander the Great (reduced to three-quarters).
its colour is quite different from that of the ground-
work of the stone. It is set in a superb frame of
enamelled gold.
170
PRECIOUS STONES.
The fig. following (Fig. 75) is a chalcedony dis
playing a bacchic bull with an ivy wreath around
his body and a thyrsus under his feet. It is one of
the most celebrated of antique engraved gems, and
bears the signature of the famous graver Hyllus.
As a specimen of modern engraving, we represent
by Fig. 76 that celebrated stone known as the "seal
of Michael Angelo." It is a small transparent cor-
nelian engraved en creux or entaille. In the small

VAAY

Fig. 75.-Cameo of Hyllus.
Fig. 76.-Seal of Michael Angelo.
space of an oval, hardly more than half an inch in
length, there are fourteen figures, besides the
scenery of a river with water-monsters and a fisher-
man. It is a bacchanalian or vintage scene, and it
recalls a part of Michael Angelo's fresco of "Judith
committing the head of Holophernes to her atten-
dant." Critics are at variance concerning this cor-
nelian: it has been ascribed to the famous engraver
Pyrgototes, with the supposition that Michael Angelo
used its design as a passage of his great fresco;
and, on the other hand, it is called a modern chef-

THE ZIRCON.
171
d'œuvre, whose engraver has been inspired by
Michael Angelo.
This stone was in the cabinet at Versailles, and
was one day swallowed by an enthusiast in gems;
but fortunately Hardion, who was exhibiting the
treasures, observed the act, and before the honest
man departed persuaded him to take an emetic for
the benefit of his stomach. The gem was in this
manner immediately recovered.
SECOND CLASS.
THE ZIRCON.
The zircon, called also the jargon, is altogether
special in its composition, being formed of silica,
united with a peculiar mineral-zircona, the oxide
of zirconium.
The zircon crystallizes in four-sided prisms, with
various modifications. Fig. 77 shows the primitive
form, and Fig. 78 a modification approaching the
form of the dodecahedron.
Generally speaking, each of the two types has its
own particular colour, which is shared by the crys-
tals belonging to it. The first is a brownish and
greenish-yellow, the second brownish-red. Werner
called the rhomboidal type hyacinth, and the pris-
matic zircon. Ancient lapidaries made the same

172
PRECIOUS STONES.
distinction, and the stone that Werner calls zircon
is their jargon of Ceylon.
The colourless crystals of the zircon are the most
Fig. 77.-The Zircon.
Fig. 78.-Modified Zircon.
valued. They take on an excellent polish, display
an adamantine lustre and fire, and will pass for dia-
monds if not too closely inspected. The zircon,
Fig. 79.-Zircon from the Cabinet of M. Drée.
accordingly, is sometimes introduced into orna-
ments, and sold to inexperienced people as a dia-
mond, a particularly gross fraud, inasmuch as the
zircon has but a very trifling value. Indeed even an

GARNETS.
173
exceptional zircon, of a beautiful olive-green tint, of
the dimensions shown in Fig. 79, was sold at the
auction of M. Drée for the sum of $16. A dia-
mond of the same dimensions, even if only a rose,
would weigh about 5 carats, and would bring not
less than $1800.
The finest specimens of zircon are brought from
Ceylon; but they are also found in Europe, in the
vicinity of Lisbon, and in France, near the town of
Puy.
GARNETS.
With materials which, though different in their
nature, are cut and placed in the same manner, it
is possible to construct several edifices resembling
each other in form and disposition.
That which Art accomplishes more or less com-
pletely, Nature realizes perfectly.
Out of substances essentially differing in their
nature she constructs well-defined and crystallized
compounds, which appear to all intents and pur-
poses identical, and yet are not so.
This phenomenon is called in science isomorphism,
from the Greek isos, equal; and morphe, form. It
was discovered by the celebrated German chemist
Mitscherlich, and the discovery is considered one of
the greatest scientific achievements of our century.

174
PRECIOUS STONES.
The group of minerals designated by the name
of garnets furnishes one of the most remarkable
applications of the grand theory of isomorphism.
Under this name are comprehended minerals dif-
fering much in colour, in specific gravity, in chemi-
cal composition, &c.; but whose fundamental form
never changes, and which even presents a very
Fig. 80.-Garnet, Rhomboidal type. Fig. 81.-Garnet, Trapezohedral type.
Garnets
small number of secondary modifications.
are always crystallized, and they appertain to the
tesseral system. Two secondary forms only are
nearly always produced, the rhombic dodecahedron
(Fig. 80), and the trapezohedron (Fig. 81).
In a scientific classification Rose, and the greater
number of mineralogists with him, admit eight
species of garnets, but two only furnish products for
jewelry; these are:-

GARNETS.
175
The Grossularia,
The Almandine.
Grossularia.-This species is a double silicate of
lime and alumina. As its constituents are col-
ourless, either alone or combined, we should meet
with limpid garnets devoid of any tint. Such gar-
nets, in fact, are found in certain localities of Nor-
But as
way, Mexico, and the Ural Mountains.
iron-which Haüy has called "the great colourist
of nature"-is so extremely abundant, it becomes
introduced in proportions more or less considerable
into the grossularias, and the result is that the
limpid garnets become tinted with green, clear red,
orange red, &c., according to the quantity of iron
combined. The varieties of Ala in Piedmont, so
remarkable for the vivacity of their lustre and the
purity of their forms, are grossularia. There are
also certain yellow varieties in Siberia which re-
semble in colour the spinel ruby.
The analysis of a colourless garnet of the Ural
has given the following results:-
Silica,
Alumina,
Lime,
38.66
24°19
•
37 15
100˚00
Almandine. This species is a double silicate of
alumina and iron; it is the grossularia with its lime
replaced by oxide of iron. Often, however, the
lime is not completely replaced, and the iron is not

176
PRECIOUS STONES.
the only principle substituted, but then it is accom-
panied by an equivalent proportion of magnesia or
oxide of manganese.
The beautiful variety of yellow garnet called
pyrope belongs to the almandine species. It differs
only from the type by a little quantity of the oxide
of chromium taking the place of an equivalent quan-
tity of the other bases. This substitution is re-
garded as perfectly regular by the mineralogist, but
it produces a very agreeable colour, and gives com-
mercially an altogether peculiar value to the
pyrope.
It is to the almandine species also that the garnets
so well known in commerce as Bohemian garnets be-
long. They are furnished by Bohemia, Saxony,
and other parts of Germany.
The most desirable garnet is the oriental or
Syrian garnet.
garnet. Its composition varies, but its
lustre and beauty place it above all others. Its
name is not derived from Syria, as is often sup-
posed, but from the Syrian, a river in the country
called Pegu in Asia. It was from that country,
indeed, that the first specimens were brought; but
this commercial species is found equally in the Isle
of Ceylon and in Brazil.

PERIDOTE, OLIVINE.
177
EXCEPTIONAL GARNETS, AND ARTISTIC APPLI-
CATIONS OF THIS STONE.
At the sale of M. Drée's cabinet, a Syrian garnet
of an octagonal form, inch by, was sold
for $650. Another, fire-red, I inch by inch,
attained the price of $186.
Among engraved garnets may be mentioned the
head of the dog Sirius, a chef-d'œuvre of Coli,
a mask of Silenus crowned with vine-branches, a
fine bust of Hadrian in the Odescalchi Museum,
and a celebrated Venus Genetrix in the cabinet of
the Abbé Pullini at Turin.
PERIDOTE, OLIVINE.
The peridote is a stone very anciently employed
in jewelry; and as up till late years it was only
found in water-worn fragments, its form of crystal-
lization could not be determined. The recent dis-
covery, however, of well-defined crystals of peridote
on Vesuvius shows that they appertain to the right
rhomboidal prism.
The peridote is a double silicate of magnesia and
iron, with variable proportions of manganese,
alumina, and sometimes nickel. According to the
nature and quantity of the metallic compounds that
enter into its composition, the peridote exhibits
12

178
PRECIOUS STONES.
crystals of different colours. The peridote, properly
so called, is a yellow-green; other varieties have
clear olive-green tints, and are called by the lapi-
daries olivines.
The crystals of peridote are sometimes called chry-
solite, but this must not be confounded with oriental
chrysolite or cymophane.
An interesting fact attaches itself to the peridote.
It is, among all the precious stones, the only one
which has to this time had the honour of being
found in those stones dropped from space, which we
designate under the name of aerolites.
The peridotes of commerce are brought from the
Levant by way of Constantinople, but the exact
locality in which they are found is not known.
JADE.
This word is a generic term used to designate a
certain number of substances, which, while re-
sembling each other in many characteristics, differ
materially in their composition.
These common characteristics are great hardness:
wonderful tenacity, a wavy or scaly fracture, a cer-
tain oily lustre, and tints of white, greenish-white,
milk-white, and rose-white.
The best known variety is brought from China;
it is a silicate of lime and magnesia, with traces of

JADE.
179
oxide of iron, and sometimes of oxide of man-
ganese.
Another variety, greatly prized by the ancients
for its miraculous power of curing colics and the
bites of venomous insects, is called nephritic jade,
or nephrite stone; it is of a pale-green colour,
sometimes with a slight tinge of lilac.
Antique objects made of jade are so hard that
they can only be cut by the diamond; and as these
objects are many of them of considerable dimen-
sions, and their number is too great to suggest such
difficult labour, it is supposed that when this jade
was taken from the mine it was easily cut, and
afterwards attained its hardness by exposure to the
air, or perhaps by the direct action of fire.
The jade of Saussure, found in Switzerland, is a
species differing somewhat from the Indian jade;
and the axe-stone jade is a product of South
America. It has been called the amazon stone, and
Humboldt says that the Caribbees used the jade
stone as amulets, cut in the shape of the Perse-
politan cylinders, longitudinally perforated, and
covered with inscriptions.
The principal mines of European jade are in
Turkey and in Poland, where it is wrought into
knife-handles, daggers, &c., and is softer than the
oriental jade.
The Chinese are particularly fond of jade, and
180
PRECIOUS STONES.
•
:
work it into objects of great beauty. A sceptre of
white jade was sent as a present from the Emperor
of China to Prince Albert of England.
TOURMALINE.
The tourmaline holds but a secondary rank
among those gems that are used for ornament,
but, from a scientific point of view, it is well worth
attention.
The modern tourmaline is the lyncurium of the
ancients. It is also called schorl, especially in
Germany, from the name of a village in Saxony,
where it is very abundant.
Its composition is very complex; there are, how-
ever, certain elements which are characteristic of it,
namely, boracic acid, silica, and alumina. In all
tourmalines, also, there is an alkaline base, some-
times potash, sometimes soda, sometimes lithia, or
a mixture of all. There is found in it also mag-
nesia, lime, oxide of iron, and oxide of manganese.
The tourmaline is always crystallized, and its
crystals appertain to the rhombohedral system.
The crystals are in the form of longish prisms,
sometimes with six faces, sometimes with nine,
and in this case, in consequence of the obliteration
or partial obliteration of faces, they terminate in
such forms as shown in Fig. 82.

LABRADORITE.
181
The tourmaline assumes a great many colours,
and accordingly receives a great number of names.
The Isle of Elba produces specimens from white
to black; a species from Siberia is a beautiful red;
from the Brazils both green and blue tourmalines
are brought; and from Sweden a fine indigo-blue
called indicolite. Berlin-blue tourmaline is called
Fig. 82.-Tourmaline.
Brazilian sapphire; and there are green shades,
which are called Ceylon or Brazilian emeralds.
These blue and green tourmalines show in the
most pronounced manner the phenomenon of di-
chroism.
LABRADORITE.
The beautiful stone of Labrador, unknown until,

182
PRECIOUS STONES.
4
about a hundred years ago, it was discovered in the
Island of St. Paul, near the coast of Labrador, is
the type of one of the four great species formed by
Rose, at the expense of the ancient group of the
felspars. Its specific gravity is 2'6 to 2'7.
і
The labradorite is called sometimes the opaline
felspar, because it resembles the opal in its beauti-
ful reflections of colours. The finest colours are
a play of blue and green upon gray. Yellow and
bronze-red are less common; and a pearly-gray and
purple-red still more rare.
The labradorite is essentially formed of silica,
alumina, lime, and soda.
It has been found in its crystallized state
scattered through volcanic productions, and notably
in the lavas of Etna.
LAPIS-LAZULI.
The lapis-lazuli is a mineral whose beautiful blue
colour varies from the palest tint to a deep blue,
nearly black. The finest is a uniform colour of
deep azure inclining to purple. Its specific gravity
is 2.6.
Chemists differ its analysis; but it is known to
contain silica and alumina, with a supplement of
soda, lime, and sulphur. Its colour is of such en-
during quality that the preparation made from it,
}

LAPIS-LAZULI.
183
called ultramarine, is never deteriorated by the
air, and is consequently of the utmost value to ar-
tists. Lapis-lazuli takes a beautiful polish, and is
converted into many exquisite articles of ornament.
It is found in Persia, Siberia, and Chili, but the
most esteemed specimens are brought from China.
APPLICATION TO THE FINE ARTS OF LAPIS-
LAZULI.
Lapis-lazuli is frequently engraved, and it is
carved also into cups and vases.
The French crown jewels contained some beauti-
ful objects in lapis-lazuli; among them a cup in
the form of a boat, of large dimensions, and valued
at $37,200, and a sabre with a handle of lapis-lazuli
given to Louis XVI. by Tippoo-Saib, valued at
$1116.
Many beautiful specimens were exhibited at the
Paris Exhibition; exquisite carving by Rudolphi, a
marine shell carved of azure lapis-lazuli, finely
mounted by Morrel, and chef-d'œuvres by Dupon-
chel and Jarny.
In the Orlof palace at St. Petersburg some of the
apartments are lined with this beautiful stone.

184
PRECIOUS STONES.
MALACHITE.
Malachite, or "vert de montagne," is a hydrated
carbonate of copper, or rather "a stalagmitic form
of the green carbonate of copper" found in Siberia,
Norway, and the Ural Mountains, and lately in
South America. It is rarely found in masses
weighing more than from ten to twenty pounds,
and good specimens have a very high value. Its
specific weight is 4.
Malachite takes a fine polish, and its varied
shades of green, disposed with a thousand caprices,
or in diverse zones, give it a pleasing effect. Beads
and pendants of it are occasionally seen in jewelry,
but its chief use in art is for ornaments of larger
dimensions, such as boxes, paper-weights, statu-
ettes, &c.
At St. Petersburg an exceptionally large slab of
malachite 34 inches by 18 broad and 2 thick, is
valued at $5294.
Under the First Empire an apartment in the
Grand Trianon was furnished with beautiful objects
all made of malachite, and presented to Napoleon
I. by Alexander of Russia.
Attempts have been made to engrave malachite,
but owing to its soft texture and multiplicity of
zones destroying artistic effect, without successful
results.

HEMATITE.
185
HEMATITE.
The hematite is a sesqui-oxide of iron occurring
with a fibrous or radiated structure in mammillated
or globular masses, and greatly resembles malachite
in the mode of its formation.
It is a very common stone, of a dark-red colour,
verging upon black. Properly speaking it is not a
precious stone, but it is mentioned here because it
is the first stone that ever was engraved. It is the
material of the cylinders and the vases engraved by
the Chaldeans, the Assyrians, the Medes and Per-
sians, and Phenicians, in the remote time to which
we refer the origin of art.

PART VI.
Pearl. Coral. Amber. Jet.
"The sea-born shell conceals the unio round-
Called by this name as always single found.
One in one shell, for ne'er a larger race
Within their pearly walls the valves embrace.
At certain seasons do the oysters lie
With valves wide gaping towards the teeming sky,
And seize the falling dews, and pregnant breed
The shining globules of th' ethereal seed."
The pearl is an animal product secreted by cer-
tain shell mollusca, of which one kind live in the
sea, and the others in fresh water. Pearls are quite
common, but those which have considerable dimen-
sions, joined to a regular form and beautiful reflec-
tions, are rare and of high price.
Formed almost exclusively of lime and of an
organic matter, the pearl is very easily acted on; as
regards resistance, it has nothing in common with
precious stones, even those most easily destroyed.
The pearl was dedicated to Venus. It is sacred to
love and beauty. In the "marriage of Cupid and
Psyche❞—a fine engraving upon sardonyx, wherein
the figures are enveloped in transparent veils, a

THE PEARL.
187
work of great difficulty in engraving upon stone-
the lovers are united by a string of pearls-emblem
of conjugal bonds-by aid of which the god Hymen,
bearing a torch, conducts them to the nuptial couch
(Fig. 83).
Трол
Enole
J. Siller.del
Rapanese
Fig. 83.-Marriage of Cupid and Psyche, engraved upon a Sardonyx.
A number of opinions have been expressed upon
the origin of the pearl. The ancients poetically
ascribed it to a drop of dew falling at morning or
evening into the opened shell.
"Brighter the offspring of the morning dew,
The evening yields a duskier birth to view."
It was once a common belief that the pearl was
a morbid production of the animal. Above all, it
has been thought that it originated in some foreign

188
PRECIOUS STONES.
substance, such as a grain of sand, or an animal
parasite, introduced accidentally into the shell.
Thi substance, it was supposed, tortured the ani-
mal, which, to free itself from the irritation, covered
it with a pearly secretion. Acting on these ideas,
the Chinese are said to have obtained pearls artifi-
cially, by piercing the shell, and slightly wounding
the animal.
There is probably some truth in these hypotheses;
but an examination of the pearl under the micro-
scope proves that such modes of formation are not
the only ones employed; and even that they do not
necessarily enter into the formation of these beauti-
ful productions. Indeed certain pearls show in their
interior spherical cavities perfectly empty; and
others, which are completely solid to the centre,
display in all their parts a regular and continuous
texture, without the least trace of any foreign
matter.
A pearl of the first quality should possess, above
all things, a fine orient, or water. By this expression
is meant a pure whiteness, joined to a lively lustre
that sparkles in the light. There are pearls, too,
which, with a white colour, show a delicate reflection
of azure. These are the most highly esteemed.
The second quality of a fine pearl is, that it
should be perfectly spherical, or regularly pear-
shaped.

THE PEARL.
189
There are a great number of pearls whose colour
has a yellowish tinge. This alone is a mark of
inferior quality.
It is very probable that pearls possessing this
yellowish shade exist normally in the shell. Taver-
nier, however, thinks that all pearls are white, and
that the yellow tint is induced by putrefied pro-
ducts, resulting from the treatment of the shells in
their places of production; the pearl-shells being
left in the open air that they may open of them-
selves after the death of the animal. The work is
thus accomplished without any expense, and with-
out risk of breaking the pearls, an accident that
occurs very frequently if the shells are opened arti-
ficially. In support of his theory Tavernier states
a fact, which, if established, would be conclusive;
which is, that yellow pearls are never found in shells
that have preserved their water.
The shells in which pearls are found belong to
several families of the large class of mollusca; but
the most important of all is the—
Avicula margaritifera, Bruguière; Pentadina
margaritifera, Lamarck. This species not only
produces the pearl, but furnishes to commerce vast
quantities of mother-of-pearl of the kind most
valued.
There is a prevailing idea that mother-of-pearl
and the pearl are of the same nature; and, in con-

190
PRECIOUS STONES.
sequence of this notion, numberless attempts have
been made to obtain artificial pearls by means of
little spheres more or less regularly cut out of
mother-of-pearl.
The experiment has never been successful. A
little serious examination of the subject proves that
there is nothing to hope from this method. Even
admitting that mother-of-pearl and pearl are the
same in composition, which has not been scienti-
fically proved, it is certain that they are not of the
same constitution. Mother-of-pearl is much harder,
and offers infinitely more resistance to the tools of
the lapidary than the pearl. But that which is
most important to be remarked is, that in the pearl
the constituent layers are concentric, while in the
pearls cut out of mother-of-pearl, the layers are
more or less parallel.
Fig. 84.-Pearl. Fig. 85.-Mother-of-pearl.
Figs. 84 and 85 establish perfectly to the eye the
complete difference presented in this respect by
mother-of-pearl and the pearl.

THE PEARL.
191
They show, at the same time, how the light must
necessarily undergo very different modifications in
the two cases, and why cut mother-of-pearl can
never have the same optical effects as the pearl.
Although pearl molluscs exist in all parts of the
world, there are but few places where their gather-
ing has become an industry. One of these places
was formerly the Red Sea, which, in the time of the
Ptolemies, produced an abundance of pearls. But
the beds are probably exhausted; at any rate they
are no longer worked. The two regions which for
a long time have produced the most beautiful pearls
are the Persian Gulf, and the Straits of Manaar
which separate Ceylon from the peninsula of
India.
More recently great quantities of pearl-oysters
have been discovered in America, particularly in
the Gulf of Mexico, upon the coasts of California,
and in the vicinity of Panama.
There have been experiments made to determine
the time necessary to the development of a pearl.
No very certain results have been obtained; but it
has been proved that at least two or three years
are necessary for the formation of a pearl of any
value.
Hitherto the pearl shells have been gathered by
divers, who, practising the pursuit from their
earliest years, end-by being able to stay nearly six

192
PRECIOUS STONES.
*
minutes without breathing at the bottom of the
*sea.
The prodigious efforts which they are obliged
to make, and the considerable pressure to which
they are subjected, result in a number of very
grave accidents. The bodies, too, of the unhappy
beings who devote themselves to this frightful trade,
are very quickly covered with sores; and very sel-
dom does a pearl-diver arrive at old age.
The remarkable appliances which render it possi-
ble to stay under the water for a long time without
much inconvenience have been introduced into the
localities where there are pearl fisheries, and will no
doubt diminish wonderfully the sad consequences
so long inseparable from this deadly trade.
Of all the objects employed as personal orna-
ments, the pearl is almost the only one that derives
nothing from art. On the contrary, all attempts
made to give it more value only end in deterio-
rating it.
Pearls were among the first substances ever em-
ployed as ornaments. As far back, indeed, as we
can look into antiquity, we find them figuring in
the first rank.
The Indian mythology speaks often of the pearl,
and attributes its discovery to Vishnu, who searched
the ocean for these ornaments to deck his daughter
Pandala. The Book of Job and the Proverbs of
Solomon also mention them. The accounts of
•

THE PEARL.
193
ancient historians show the estimation in which
pearls were held by the Babylonians, the Persians,
and the Egyptians.
Everyone knows the famous story of Cleopatra,
who, striving to rival the prodigality of Antony,
dissolved in vinegar the pearl of one of her ear-
rings, which had cost $706,800, and swallowed it.
The possibility of this fact has been contested, but
the thing is quite possible, only nothing more
nauseous than the mixture can be imagined.
This experiment may possibly have been tried
upon real pearls without success, but then probably
the action of the acid did not last long enough.
The pearl, as we have seen, is formed of carbonate of
lime, and an organic substance. The vinegar easily
effects a soluble combination with the carbonate of
lime; but as soon as the lime of the first layer is
consumed, the organic matter of a gelatinous con-
sistence continues to envelop the pearl; and as this
matter is not soluble in vinegar, nor can be attacked
by it, a protection is formed around the interior
layers, so that they are not reached by the corrosive
liquid. But by persistence, in the end even this is
penetrated, and the pearl is completely dissolved.
The passion of the Romans for pearls, like all the
passions of this people, was carried to an extrava-
gant height.
The pearl which Cæsar presented to Servilia,
18

194
PRECIOUS STONES.
•
is
sister of the celebrated Cato of Utica, had cost
$223,200. The Empress Lollia Paulina, wife of
Caligula, wore, in a set of ornaments composed of
emeralds and pearls, the value of $1,488,000. Cali-
gula himself, Nero, and other of those cruel men
whom history is obliged to name among her Roman
emperors, ornamented their buskins and strewed the
furniture of their saloons with pearls. Under the
influence of the ideas of which we have spoken
in Part ii. pearls acquired great importance in
medicine. Even in our own time they are fre-
quently employed medicinally; and in China are
chiefly valued on this account. Every year a large
quantity are absorbed generally in a dissolved
state-by the inhabitants of the Celestial Empire.
By the effects of time, and of external agencies,
pearls lose the beautiful reflections which constitute
all their value; often, too, under these influences,
they become more or less yellowish. There are
also natural pearls, of a beautiful form and ample
size, which do not exhibit these reflections, and
whose colour is generally rather deep. In both
cases they are called dead pearls. In this state
they are of very little value, and a thousand means
have been tried to give them lustre.
In certain cases the operation succeeds; in others
it is a complete failure.
With great difficulty the present writer obtained

THE PEARL.
195
a certain number of secret receipts for restoring dead
pearls to their primitive lustre. In one of these
concoctions there are eighty-three ingredients, each
one more whimsical than the last. In another the
chief ingredient is dew gathered under certain con-
ditions, and from the leaves of certain plants. One
easily traces the influence here of the idea that the
ancients entertained of the origin of the pearl.
At first glance these receipts seem only to asso-
ciate the most dissimilar elements, and those that
could not possibly have any efficacy; but the
chemist discovers in them one remarkable fact:
after the complex reactions of one substance upon
another, there remains always the definite result of
an acid liquor.
Recalling now the constitution of the pearl,
formed of concentric layers, and the facility with
which it is dissolved by an acid liquid, one can
easily see that a pearl plunged into this liquor will
be attacked, and that its exterior layer will quickly
disappear. If the pearl submitted to this operation
is only yellow and opaque exteriorly, the removal
of the layer thus modified will leave bare the nor-
mal layers, and the pearl will recover its lustre. If,
on the contrary, the layers are discoloured and
opaque to the centre, nothing can restore it. In the
first case the operation is a success; in the second
it is a failure. The reason is no longer a mystery.

196
PRECIOUS STONES.
CELEBRATED PEARLS.
The most celebrated pearl which has been seen
in modern times is described by the famous.
traveller Tavernier,
Found by an Arab in the neighbourhood of
Catifa, it was purchased in 1633, by the King of
Persia, for the sum of $260,400.
The pearl known as the Peregrina, bought by
Philip II., king of Spain, weighed 134 carats; it
was in the form of a pear, and of the size of a
pigeon's egg. It came from Panama, and was esti-
mated at more than 50,000 ducats.
Another still more famous pearl was brought
from the Indies by Gorgibus of Calais, and pre-
sented to Philip IV., king of Spain; it had the
form of a pear, and weighed 126 carats.
"How have you ventured," asked Philip IV. of
the merchant, "to put all your fortune into such
a little object?" "I knew that there was in the
world the King of Spain to buy it of me," the
merchant answered. There was but one royal
way of rewarding such faith as this, and Philip IV.
became forthwith the owner of the pearl of
Gorgibus.
The inventory of 1789 shows that the crown of
France possessed at that time pearls to the value of
$186,000, among which occurred-
PRICE OF PEARLS.
197
Ist. A round virgin pearl of a magnificent
orient, weighing about 27 carats, and estimated at
$37,200.
2d. Two pear-shaped pearls, finely formed,
and of a very beautiful orient, weighing both to-
gether 571 carats, and estimated at $55,800.
3d. Two other pairs of pearl pendants, weigh-
ing together 99 carats, estimated at $11,904.
There is also a magnificent pearl, which was
brought from Berlin by the first Napoleon, and
which was exquisitely mounted in a breastplate by
Lemonnier.
When the Princess Royal of England was married
to Prince Frederick William of Prussia she received,
among other objects of jewelry, a magnificent neck-
lace formed of thirty-two pearls. It is said that
the pearls are not all of the first choice, but the
necklace is valued at $93,000.
PRICE OF PEARLS.
Of all the substances employed in jewelry the
pearl is the one whose value it is the most difficult
to establish, because it depends upon so many
variable conditions of size, form, and colour.
The table given here is one which was made by ·
M. Harry Emanuel, to show the price of pearls
of the first choice in 1867:-

198
PRECIOUS STONES.
1865.
1867.
A Pearl of 3 grains,
$3'16 to $3.34
$3'90 to $4°27
"
4
4:65 to
5'95
5'95 to
7'44
5
""
7'62 to
9'67
8°55 to
10'78 ·
6
"
12 90 to
13 95
15°06 to
17°29′
8
19 34 to
23'80
21˚57 to
35'85
ΤΟ
"
"
37°57 to
42°22
46'87 to 51'52
12
""
29
56 17 to
70 30
65°47 to 74 95
14
"
"
70 30 to
84 25
84°25 to 93°74
16
93.
"
18
"
20
"
"
•
:.
24
30
"
•
•
93'74 to 140 61
140'61 to 186'93
186 93 to 223 20
281°23 to 337°59
393'76 to 468'90
93'74 to 140'6г.
140°61 to 186'93
186'93 to 234°36
281°23 to 337˚59
393'76 to 468'90
*
Besides the individual value which pearls possess
in common with all other precious stones, and which
is expressed in the preceding table, they have
another very important one, which we may call
associative value. Thus it happens, that two pearls
of the same form, the same size, the same colour,
&c., are worth a much higher price, if sold together,
than when sold apart. A necklace, in which the
pearls have been chosen from a great number, will
be held at double the value of a necklace where the
pearls have been picked from a smaller number,
even when the individual value of the pearls is
identical in both. In the first case the harmony
will be complete; while in the second case the eye
will detect a break in the shades in passing from
one pearl to another.
;
CORAL.
Coral is a submarine production secreted by ani-

CORAL.
199
mals forming one little tribe in the grand class of
polypi.
The colour of coral follows numberless gradations,
from an intense red to a complete white. Its com-
mercial value varies enormously according to its
colour, the rose tints being the most esteemed.
Different varieties are named according to the pre-
cise shade of colour, as "écume de sang," "rose,"
"fleur de sang," &c. One hundred shades of red
coral are distinguished at Marseilles.
Until the eighteenth century it was believed that
coral was a small tree living and developing itself
under the sea. It was only in 1727 that a French-
man, Peyssonnel, established its real nature, show-
ing that the flowers of this tree were radiated
animals, and that the coral was gradually formed by
them.
Coral is fixed to the solid body which it rests
upon by a kind of conical outspread foot. The
nature of the support would seem to be a matter of
indifference, so long as it is solid. The stems of
coral are directed often in an opposite direction to
those of plants, inasmuch as, being attached to the
under side of rocks, they grow downwards.
The coral that is known in commerce presents
itself in the form of little trees more or less branched;
but in the living coral all the branches are covered
with a sort of pale-coloured fleshy rind, glossy and

200
PRECIOUS STONES.
polished, showing at its surface a great number of
cells, each one of which incloses a polype. These
very elegant little animals are what were taken for
the flowers of coral.
Fig. 86 shows the polypi of the coral in different
degrees of expansion.
Fig. 86.-Polypes of Coral in different degrees of development.
It will be seen that their eight extended tenta-
cules, pointed and incised along their edges, joined
to the completely white colour of the animals
themselves, present an ensemble which a century
or two ago might well be taken for a flower.
Stripped of its coating, the coral shows a great
number of parallel, longitudinal, and very often

CORAL.
201
sinuous striæ, stretching from one end to the other
of the axis. Its texture is extremely compact, this
being precisely that which permits it to take a per-
fect polish, and gives it a great part of its value. But
this texture is not homogeneous; on the contrary,
it is perfectly organized. To be convinced of this
we have but to break or cut a branch of coral per-
pendicularly to the axis, and to submit the part
left bare to the action of an acid. The different
parts will be unequally attacked, and a radiated
texture becomes at once apparent.
Coral exists probably in all the seas of warm and
temperate regions, but the Mediterranean furnishes
to commerce the greater part of this product.
To gather it there has been for a long time used
a sort of dredge called salabre, formed of two pieces
of wood or iron, disposed in the form of a St.
Andrew's cross, upon the extremities of which nets
are fastened to receive the coral detached by the
reiterated blows of the instrument.
There are also, as in the search for pearls, divers
who plunge to a considerable depth to gather this
beautiful production. But already the modern
appliances for exploring the sea-depths have been
employed with complete success to the gathering
of coral...
There enters into the composition of coral 88 to
100 parts carbonate of lime, a little magnesia,

202
PRECIOUS STONES.
some traces of organic matter, and about. I part to
the 100 of oxide of iron.
Coral possesses a very interesting property,
- which, beyond doubt, contributed to elevate it to
the exceptional rank that it has occupied in medi-
cine, even to the nineteenth century. Certain per-
sons cannot wear against their skin any objects of
coral without discolouring them, and this pheno-
menon is general among all invalids. The ancients
asserted that if a person wearing a necklace of coral
was on the verge of an illness, the coral showed dis-
coloration before the least consciousness was felt
of the approaching malady.
Naturalists and chemists have of course inquired
what is the nature of this singular colouring matter
that is so exceedingly impressionable? So far, the
only colouring substance which chemistry has de-
tected in coral is oxide of iron, one of the most fixed
in nature, and one which, under the circumstances,
cannot enter into new and colourless combinations;
consequently the problem has not yet reached a
solution.
AMBER.
Amber has been known from earliest antiquity.
The celebrated founder of the Ionian school of
philosophy, Thales, who lived 600 years before
our era, speaks of the property which, above all,
2

AMBER.
203
contributed to render it celebrated—that of attract-
ing light bodies when it was rubbed. It is from the
Greek name of amber, electron, that our modern
term electricity is derived.
To explain the origin of amber, the Greeks had
one of those graceful traditions characteristic of the
young and marvellous genius of that people. They
said that the sisters of Phaethon, weeping for the
death of their brother, were changed into poplar
trees upon the banks of the Eridanus (Po), and
that their tears were transformed into amber.
It is to this legend that the tender and har-
monious poet of the Metamorphoses alludes when
he says:—
"Stillataque sole rigescunt
De ramis electra novis, quae lucidus amnis
Excipit et nuribus mittit gestanda Latinis.”
:
"The juices distilling from these new trees,
solidified by the sun, are received by the shining
river, and borne as offerings to the brides of Italy."
Chemical analysis shows that there are in 100
grammes of amber 81 grammes of carbon, 7:30 of
hydrogen, 6.75 of oxygen, and some traces of clay,
alumina, and silica, amounting altogether to about
3 grammes.
This is exactly the composition of resin; indeed
amber is itself a resin.
66
Amber," said Pliny, "trickles from the pith of

204
PRECIOUS STONES.
:.
certain trees resembling pines." This quotation
proves that the Roman naturalist considered amber
as a contemporary production. He was right so
far-amber is a resin; but it is a fossil resin.
The places most rich in amber are the borders of
the Baltic Sea, between Dantzic and Memel; it is
found also in Denmark, in Norway and Sweden, in
Poland, France, and England, and in different parts
of Asia and America..
Wherever amber is found it is associated with
lignites... It is nearly certain that the resinous trees
which produced these combustibles secreted amber,
since it is not rare to find fragments of amber
lodged in the midst of beds of lignite.
The presence of organized bodies, and particu-
larly insects imprisoned in amber, was well known
to the ancients, and is mentioned by the poet
Martial in particular.
The illustration given here (Fig. 87) shows
a lizard embedded in a piece of amber. The origi-
nal fragment of amber belonged to the collection of
Kircker, and was presented to him by the Duke of
Brunswick.
The amber which is most esteemed is translucid,
and of a beautiful lemon yellow; but there are also
varieties semi-opaque, and one of a pale yellow
with veins and spots of dead-white that is much
esteemed.

AMBER.
205
Amber is worn as an ornament principally in the
East, where it is cut into beads, and threaded as
BANUFOUR
BLACLARTE
Fig. 87.-Lizard imprisoned in a fragment of Amber.
necklaces. In western countries it is prized merely
as serving to fabricate small objects of art, especially
the mouth-pieces of pipes and cigars. This latter


206
PRECIOUS STONES.
·
usage in the East is justified by the prevalent be-
lief that amber never will allow the transmission of
any infection. This of course would be a highly
valuable quality, but unfortunately there is nothing
to prove its existence.
Lumps of amber are generally very small, but
occasionally a piece is obtained of considerable
size; as, for example, a specimen of amber in the
Royal Museum at Berlin, which weighs 18 pounds.
Amber is wrought on the turner's lathe by steel
instruments, and polished on a leaden wheel with
pumice stone and water.
JET.
Jet, a beautiful black substance, is in point of
fact a lignite produced by the decomposition of
resinous vegetation buried in the earth thousands of
ages before the historic times. Yet in mines of
lignite jet is rare.
The hardness, the fineness, and the compactness
of its tissue probably result from the peculiar
nature of the trees from which it has arisen. How-
ever this may be, it is the union of these qualities
that render jet capable of receiving a very brilliant
polish, and assert its place as a valuable object of
jewelry.
Jet is found in all places where amber exists,

JET.
207
and in many localities also where amber is not
found.
Jet was formerly much more highly valued than
at present. In the last century, Aude, in France,
alone employed 1200 workmen on this substance.
At Whitby, in Yorkshire, jet is still the object of
a considerable industry. But the imitations of
this substance have largely taken its place; even
the poor imitation of varnished glass is received
with favour. A much better substitute for it would
be real stones of little value, such as black tour-
maline, melanite, and obsidian.
Jet is worked by means of a lathe and horizontal
sandstone wheels, smooth at the centre, but rough
at their circumferences, so that the workman may
cut and polish a stone on the same wheel.
Among ancient ornaments of jet are some curious
anklets and bracelets belonging to the early period
of British history.
A complete set of jet ornaments was found in
; two stone coffins deposited under the chief entrance
of Saint Geréon, Cologne, when that church was
repaired in 1846. They are supposed to have been
the ornaments of some priestesses of Cybele.

:
PART VII.
Artificial Production of the Diamond. Boron Diamond-Cagniard
de Latour-Gannal—MM. Despretz and de Chancourtois.
1
"The liquid ore he drained
Into fit moulds prepared, from which he formed
First his own tools: then what might else be wrought.”
Before we give an account of the attempts that
have been made to produce the diamond by arti-
ficial means, it is necessary to state a few facts re-
garding two other simple bodies whose properties
very closely resemble those of carbon, and which
have an important bearing on the subject of which
we are about to speak. These bodies are boron
and silicon.
•
Not only do these bodies present exactly the
three modifications presented by carbon-that is to
say, they are either crystallized, graphitoid, or
amorphous-but the crystallized boron so closely
corresponds to the real diamond that it has been
named from analogy the boron diamond.
Crystals of boron are limpid and transparent;

BORON DIAMOND.
209
sometimes coloured garnet-red, and sometimes
honey-yellow, by the presence of foreign matters.
Their refrangibility can only be compared to that of
the diamond, and they present the same effects of
reflected and refracted light. They possess the
quality of hardness, too, in such a degree as to
scratch the oriental ruby and corundum; and M.
Froment has used a crystal of boron to scratch the
surface of a diamond.
The cutting of the diamond with powder of boron
was attempted by M. Voorzanger, of Amsterdam,
with entire success; only that a larger quantity was
used than would have been necessary of diamond-
dust, and the work was accomplished more
slowly.
The same success attended the cutting of an ex-
ceedingly hard diamond in the collection of the
Normal School at Paris. Its angular edges, and a
furrow which marred it, were removed by a wheel
covered with powder of boron. M. Guillot, who
directed the experiment, confirmed the observation
of M. Voorzanger concerning the superlative quali-
fications of boron-dust for cutting and polishing
diamonds.
:
It has been further observed that the greater
number of the powerful agents at the disposal of
modern chemistry are without action upon boron.
'It is," says M. Malaguti, “the most unalterable of
14
210
PRECIOUS STONES.
simple bodies; and if the day comes when it can
be obtained in large crystals, it may replace the
diamond."
Böron is extracted from boric acid, a production
elaborated by nature in the depths of the earth,
and whose appearance at the surface is one of the
curiosities of natural chemistry.
In certain volcanic districts of Tuscany jets of
hot steam, mixed with carbonic acid, nitrogen,
hydrochloric acid, &c., and also a small quantity of
boric acid, issue from openings in the soil called
soffioni or fumarolles. Round these soffioni circular
basins of various diameters are constructed, into
which the water of neighbouring springs is con-
ducted. The gaseous jets, forcing their way through
the water, impregnate it with the boric acid, the
quantity held in solution being increased by letting
the water flow through a series of basins, in each of
which it receives an additional supply of the acid.
When it is sufficiently charged with the acid it is
admitted into the final reservoir, where it is allowed
to stand for a time and deposit its earthy particles.
The clear solution is now run off, concentrated in
boilers by the heat of the jets themselves, and the
acid obtained by evaporation.
The manner in which MM. Deville and Voëhler
obtained crystallized boron, once so difficult to ob-
tain, is as follows:-
BORON DIAMOND.
211
:
Into a charcoal crucible 80 grammes of alu-
minium is introduced in large morsels, and 100
grammes of boric acid reduced to fragments. This
crucible is placed with charcoal paste in a crucible
of plumbago, and the whole is subjected to the
action of heat in a furnace producing a heat capable
of easily melting pure nickel. This temperature is
kept up for five hours; and when, after the cooling,
the crucible is broken open, it is found to contain two
distinct layers. The lower layer is vitreous, and
formed of boric acid and alumina; the other is
metallic, gray, and cavernulous, and is roughened
and impregnated throughout its whole mass with
little crystals: this is crystallized boron.
The mass in which these crystals are distri-
buted is formed principally of aluminium, but it
contains also variable quantities of iron and of
silicon.
The whole is boiled in a lixivium of soda, of
medium concentration, when the aluminium dissolves.
That which remains is boiled with hydrochloric
acid, and the iron is thus removed. The part not
yet attacked is treated by a mixture of hydrofluoric
acid and nitric acid, which removes the last traces of
silicon. The boron, which has not experienced the
slightest action under the influence of the preceding
agents, remains as the definitive residue.
The boron thus obtained, however, is not per
212
PRECIOUS STONES.
fectly pure; its analysis by M. Deville gives the
following results:-
Boron,
Aluminium,
Carbon,
89'1
6'7
4'2
100'00
It is very remarkable that this proportion of car-
bon (more than 4 to 100) does not prevent the
boron from being transparent; and what is still
more extraordinary is, that the boron becomes
more and more transparent as the proportion of
carbon increases.
M. Deville's conclusion is therefore inevitable,
viz. that it is nearly certain that the carbon con-
tained in the crystallized boron is present there in
the state of diamond.
We perceive, then, that boron is worthy of the
utmost attention, as being capable of affording a
special diamond, and for its possible concurrence in
the artificial production of real diamonds.
The properties of silicon being the same as those
of boron, we need not pass them in review here.
ATTEMPTS TO PRODUCE THE DIAMOND.
Two hypotheses arrest consideration in examining
the probable origin of the diamond; the first con-
ceives of carbon as having been melted by a strong
heat, and the diamond having crystallized in an
ARTIFICIAL DIAMOND.
213
excess of liquid; the second supposes a body capable
of dissolving carbon, and allowing it to crystallize
by evaporation.
Another theory was advanced by Sir David
Brewster concerning the origin of the diamond.
He supposed that this beautiful gem is of organic
origin, and he was led to this opinion by examining
the diamond microscopically, when he discovered
certain striations and dispositions that resembled
the fibres of organic substances, and particularly of
certain species of wood.
These are but suppositions, however, and we
really know nothing for certain regarding the origin
of the diamond. The most we can say is that it is
very improbable the diamond was produced under
the action of a high temperature.
The knowledge of the chemical composition of
the diamond is so recent that all the experiments
made with the least chance of success to reproduce
it have occurred within the last half century.
In 1828 two interesting experiments were made
nearly at the same time by Cagniard de Latour
and Gannal; De Latour presented his results to
the Academy of Sciences, Oct. 10, 1828; and those
of Gannal were presented the 23d of November the
same year.
Cagniard de Latour sent to the Academy of
Sciences ten tubes containing a number of light-
►
A
214
PRECIOUS STONES.
:
**
brown crystals, some of which were of considerable
dimensions. They were brilliant, transparent, and
harder than quartz. They were examined by MM.
Thenard and Dumas.
Submitted to an intense heat in contact with the
air, the crystals experienced not the slightest
change, a proof sufficient in itself that they were
not of the nature of the diamond. Besides, not-
withstanding their considerable hardness, they were
easily scratched by the latter gem. The conclusion
of the academical savants was, that the pretended
diamonds were merely silicates or artificial precious
stones.
The experiments of Gannal gained more renown.
Specimens of his productions were sent to M.
Champigny, director of the workrooms of the jewel-
ler Petitot, who examined them with care; and
having satisfied himself that they scratched steel,
and could be scratched by no metal, that they were
of pure water, and displayed a brilliant lustre, con-
cluded that these little bodies were nothing else
but diamonds. This declaration, emanating from
a man well versed in the special trade, created an
excitement, and even a panic in the diamond trade.
The process by which Gannal obtained his dia-
monds was very simple.
He introduced carbon disulphide and water into
a matrass, with morsels of phosphorus, which in the

ARTIFICIAL DIAMOND.
215
disulphide dissolved rapidly. He hoped that this
phosphorus would slowly absorb the sulphur of the
disulphide of carbon, and that the carbon, reduced
gradually to an elementary state, would crystallize.
Carbon disulphide and water will not mix to-
Fig. 88.-Gannal's arrangement for the Production of the Diamond.
gether; and the former being much the most dense,
occupied the bottom of the vase. obce
Between the two layers a pellicle formed which
strongly reflected the light when exposed to it.
In time this layer was augmented; and, at the
end of several months it was composed of a con-
glomeration of little solid bodies, which were sepa-
rated from the liquid by filtration through a
chamois-skin. These little bodies were the crystals
pronounced by M. Champigny to be diamonds-an
opinion that was utterly erroneous. How they

216
PRECIOUS STONES. ·
came there is not known, but it is probable that
either the substances made use of were not pure,
or that some foreign body or bodies had found-
their way into the matrass.
The man who has most effectually disturbed the
slumbers of the possessors of diamonds, by agitating
the question of their artificial reproduction, is M.
Despretz.
This patient and persevering chemist organized a
series of experiments founded at first on the belief
that the diamond was formed by igneous means.
In his first attempts, accordingly, he submitted
carbon to the action of the most intense heat that
he could possibly command; having for this pur-
pose united and arrayed all the Bunsen piles that
he could procure at Paris, and so obtained a current
of prodigious intensity.
The carbon was immediately reduced to vapour,
and was soon deposited in the form of fine dust on
the walls of the vessel in which it was contained.
M. Despretz would have it that the carbon had
been volatilized; and no one who attended his lec-
tures at the Sorbonne can forget the profound dis-
dain with which he would exhibit the glass globe
all blackened interiorly, and exclaim, "And yet
there are people who maintain that carbon cannot
be volatilized!" With all due respect for this emi-
nent opinion, it is probable that the, carbon was not

ARTIFICIAL DIAMOND.
217
volatilized, using that word in its common accep-
tation, but that it was merely molecularly dis-
sociated. However this may have been, the results
were completely inadequate to the production of
the diamond.
Violent means having failed, M. Despretz changed
the system. For the currents of the pile, intense
Fig. 89.-M. Despretz's arrangement for the Production of the Diamond.
and incessant, he substituted currents of induction,
intermittent and feeble; and in place of continuing
their action for several hours, maintained them in
activity during entire months.
The results of his new experiments M. Despretz
submitted to the Academy of Sciences.

218
PRECIOUS STONES.
He made use of a glass vessel similar and simi-
larly fitted up to that known as the electric egg
(see Fig. 89). To the lower rod he attached a
cylinder of pure carbon, an inch or so in length,
and nearly half an inch in diameter. To the upper
rod he affixed a bundle of fine platina wires. He
now exhausted the air from the balloon, and the
distance from the wire to the carbon being about
two inches, he then passed an inductive current by
Ruhmkorff's apparatus.
The luminous arc was suffused with a red tint
on the side next the carbon to a short distance
from the platina; the part which enveloped the ex-
tremity of the platina wires was a violet-blue.
This disposition of the apparatus was constantly
maintained; and the experiment lasted more than
a month without interruption, excepting the time
necessary to recharge the pile. At the completion
of this time a slight black layer of carbon had been
deposited on the wires. This layer, viewed through
a magnifying glass, presented nothing very dis-
tinct; but to the compound microscope, with mag-
nifying power of about thirty diameters, it offered
several interesting features. Upon the wires, and
especially upon their extremities, certain separate
points were discoverable, which appeared to belong
to octahedral crystals.
An experienced crystallographer confirmed this

ARTIFICIAL DIAMOND.
219
view, and recognized octahedrons, both black and
white, the black being truncated at their ex-
tremities.
In another experiment M. Despretz fixed a cylin-
der of pure carbon to the positive pole of a weak
Daniell pile, and a platina wire to the other pole;
he then plunged both poles into slightly acidulated
water. The experiment lasted two months; the
negative wire or pole became covered with a black
coating, but nothing was discovered in it under the
microscope.
The products of the experiments were then sent
to M. Gaudin to test upon hard stones. He proved,
in the presence of M. Despretz and others, that,
mixed with a little oil, the substance which had
enveloped one of the twelve platina wires suf-
ficed to polish in a very little time several rubies.
The black powder deposited in the water served to
give similar polish, but it required longer time. As
it is known that the diamond is the only substance
that polishes the ruby, M. Gaudin did not hesitate
to consider both these substances as the powder of
the diamond.
Two conclusions may be derived from the facts
we have just stated: 1st, that it is probable that
the diamond is not of igneous origin; 2d, that M.
Despretz has really obtained artificially the true
diamond. This is the opinion of men of the
220
PRECIOUS STONES.
..
highest authority, and in particular that of · M.
Dufrénoy.
The last contribution made to the interesting
question of the production of the diamond was
made by M. de Chancourtois. He based his theory
upon phenomena presented by the solfataras, where
sulphuretted hydrogen under the influence of a humid
oxidization, is transformed slowly into water and
sulphurous acid, and deposits crystallized sulphur.
He proposed to produce upon carburetted hydro-
gen reactions of the same order. Under the in-
fluence of a humid oxidization all the hydrogen is
transformed into water, one part only of the carbon
into carbonic acid, and he thought it possible that
the remainder, being slowly deposited, might crys-
tallize and form diamonds. As a means of verifi-
cation, M. de Chancourtois suggested the very slow
passage of carburetted hydrogen in a mass of sand
containing putrescible matter. Five years have
elapsed since the expression of these views, and it
does not appear that they have yet led to any
positive result.
The question still remains-Is there any reason-
able probability that the diamond will yet be pro-
duced artificially? This question we must answer
in the affirmative. When it is considered how per-
fectly substances much more complex in com-
position, and complicated in crystalline constitution,

ARTIFICIAL DIAMOND.
221
have been artificially produced; when it is con-
sidered, too, what definite results were furnished by
the second series of the experiments by M. Despretz
-for in such a case the size of the crystals is a
matter of indifference there seems to be no reason
for serious doubts of the possibility of the artificial re-
production of the diamond. Undoubtedly it will be
a discovery from which the diamond-merchants and
owners of diamonds will have much to suffer; but
in this, as in other cases, the loss that will fall upon
a small section of the community will be outweighed
a thousand times by the advantages which arts and
industry in general will derive from the discovery.

PART VIII.
Artificial Production of real Precious Stones.
Results obtained.
Becquerel. Ebelman. Gaudin. Henri Sainte-Claire Deville.
De Sénarmont. Daubrée. Durocher. Sainte-Claire Deville and
Caron, &c.
"Beset with emeralds
And diamonds, with sparkling rubies red
In checkerwise, by strange invention."
We have seen that the elementary constituents of
precious stones must have existed once in a con-
dition that allowed them to move freely; and that
this condition was obtained by one of three
general methods-
Ist.-Direct fusion of the substance by a suf-
ficient heat.
2d.-Dissolution at variable temperatures of the
mineral substance in a foreign body, and complete
or partial volatilization of the dissolvent; or crys-
tallization without evaporation under the influence
of natural forces, either alone or aided by heat,
electricity, &c.
3d.-Prior reduction into vapour of substances
destined to react upon each other.

ARTIFICIAL PRODUCTION.
223
To the first method belong the results of the
observations of Mitscherlich upon the mineral
species which are naturally produced in furnaces
where metals are reduced; the direct reproduction
of several minerals by Berthier; and, above all, the
fusion of alumina and of silica, by M. Gaudin.
The second method comprehends the remarkable
results of Ebelman; that which M. de Sénarmont has
employed, but in which intervenes a new element,
that of a very strong compression; and lastly, that
of M. Becquerel, but with still another element, the
action of a feeble electric current.
The third method includes the results obtained by
MM. Daubrée, Ebelman, Durocher, Henri Sainte-
Claire Deville and Caron, &c.
FIRST METHOD.
If any one should say I am going to produce a
fire of enormous power, without employing any
substance but water, he would run the risk of being
considered a fool, since fire and water have always
been considered the antipodes of one another.
Even modifying the announcement, and saying—
I am about to produce an intense fire by means of
elements derived exclusively from water, hardly
makes the proposition appear more plausible, yet
nothing can be more rigorously exact.

224
PRECIOUS STONES..
Water is composed of two bodies, which, in the
present state of knowledge, are considered simple:
they are two gases—one called oxygen, the other
hydrogen. If a mixture of these two gases is made,
and if to this mixture an ignited body is applied,
the two gases combine and form water; but at the
same time there is a production of vivid light, and a
development of a great quantity of heat. These
two effects attain their maximum when the mixture
is formed of one volume of oxygen and two of
hydrogen.
If, instead of forming the mixture immediately,
we arrange so that the two gases arrive separately,
in two uniform and continuous streams, at an orifice
of small diameter, and if an ignited body is applied
to this orifice where the gases meet and combine,
the mixture takes fire. As the two gases are con-
stantly renewed at the orifice, the combustion is not
interrupted; and a jet of flame is attained analo-
gous to that of a gas-burner. It gives out little
light, but develops an exceedingly elevated tem-
perature. The contrivance is called the oxyhydro-
gen blowpipe, and is in common use among
chemists and others.
By aid of this instrument M. Gaudin melted
silica and alumina, and artificially reproduced the
corundum.
The corundum, as we have seen, is crystallized
ARTIFICIAL PRODUCTION.
225
?
alumina.
To obtain it M. Gaudin heated ammonia
alum and potash alum: the enormous heat de-
veloped by his apparatus volatilized the potash, and
the alumina crystallized. Rubies were obtained in
this manner; and M. Dufrénoy has found in these
productions the rhombohedral form, and the triple
cleavage proper to the corundum. Finally, M. Mala-
guti has established, by the analysis of these crys-
tals, that they contain 97 to 100 parts of alumina,
and 2 of silicate of lime; a composition analogous
to that of the ruby.
The experiments of M. Gaudin date back to 1837;
this date gives the priority to this ingenious phy-
sicist for the artificial production of the corundum.
It should nevertheless be noted that more than
ten years before the work of M. Gaudin, a man who
has left a deep impress on science, Berthier, basing
his experiments upon chemical proportions, repro-
duced a great number of minerals, such as peri-
dote, pyroxene, &c., by bringing their elements
together at a high temperature.
·
SECOND METHOD.
In the year 1823 M. Becquerel, one of the most
eminent of French physicists, formed the idea of
using the currents of the voltaic pile to determine
combinations, and not merely decompositions. pa
15

226
PRECIOUS STONES.
Instead of employing powerful currents, such as
were used to produce decomposition, he applied to
his purpose very feeble currents, and the results ob-
tained surpassed his expectations.
The simple apparatus which he used is shown in
Fig. 90. It is a tube curved in the form of the
letter U. The curved part is filled with clay, to
prevent the liquids contained in the branches from
Fig. 90.-Voltaic Apparatus of M. Becquerel for the Production of Crystals.
ind
The
flowing together, without interfering with the pro-
duction of molecular actions and transports.
two liquids are, moreover, placed in direct com-
munication by means of a metallic wire.
One of the substances reproduced by M. Bec-
querel was the sulphide of silver crystallized.
In the left branch of his tube he placed a satu-
rated solution of nitrate of silver, in the right branch

ARTIFICIAL PRODUCTION.
227
a solution of sulphide of potassium, and established
a communication between the two liquids by the
aid of a silver wire. Silver was deposited on the
left-hand wire, and crystals of the double sulphide
of silver and potassium on the right; but the sul-
phide of potassium being rapidly destroyed by the
nitric acid, there remained on the wires in the clay,
and on the walls of the tube, perfectly defined crys-
tals of sulphide of silver, presenting all the charac-
teristics of natural crystals. As the current was
very weak, the crystals took long to form; some of
them from seven to eight years.
The method by direct fusion could only be ex-
pected to produce fusible minerals. The electric
method had given neither a silicate nor an alumi-
nate; and, as crystallized bodies belonging to these
classes are by far the most important, Ebelman
set himself to solve the problem of their pro-
duction.
Every one knows that if crystalline substances—
such as salt, for instance-are dissolved in water,
and the solution is allowed to stand in the open
air, the water will disappear after a time, and the
substance that was dissolved in it will be left in the
shape of solid crystals.
Reasoning by analogy, then, Ebelman came to
the conclusion that he must find some body capa-
ble of dissolving infusible combinations without

*-228
PRECIOUS STONES.
·
contracting combinations with them, and capable of
being reduced to vapour at a still higher tem-
perature.
Experiment taught him that boric acid possessed
the requisite properties in a high degree.
Being director of the manufactory of porcelain at
Sèvres, he profited by the high temperatures de-
veloped in the furnaces to make some very in-
teresting experiments, which were afterwards pro-
duced with still greater success at the continuous
fires of furnaces placed at M. Ebelman's disposal
by M. Bapterosses, fabricator of buttons of ceramic
paste.
#
Mixtures in proportions corresponding to the
composition of the stones to be produced were
placed in capsules of platina along with boric acid,
and the whole was submitted to a high temperature.
The boric acid first melted, and afterwards volati-
lized, and, as Ebelman had anticipated, the sub-
stances that it held in solution crystallized.
In this way he produced the spinel ruby so per-
fectly that it could not be distinguished by Dufré-
noy from the natural stone. This was effected by
subjecting a compound consisting of proper pro-
portions of alumina, magnesia, the green oxide of
chromium and boric acid to a high temperature in
the muffle of a furnace for eight days. He obtained
crystals measuring 0·197 inch on a side.

ARTIFICIAL PRODUCTION.
229
It is,
The method employed by M. Sénarmont is the
method of dissolution by means of water.
without doubt, the method employed by nature in
caverns and calcareous crevasses, where, after a
number of years, often very small stalactites of
crystallized carbonate of lime are produced. These
productions, and the phenomena of thermal springs,
where the pressure and heat are often very high,
and the deposits of mineral waters, suggested to M.
de Sénarmont the method of his experiments.
He introduced into the most resisting sort of
glass tubes the elements of the substances he wished
to produce. He placed together gelatinous silica,
and a body susceptible of furnishing carbonic acid
by the action of heat (bicarbonate of soda), and
having closed the tubes at the lamp, submitted
them to variable temperatures and variable
pressure.
By this process M. Sénarmont obtained a great
number of crystallized minerals, the most remark-
able of which was quartz.
THIRD METHOD.
M. Daubrée had pointed out in 1841 the prin-
ciple upon which, in 1849, he produced artificially
a certain number of crystallized minerals. The
idea was to compel the vapour of water to react at
230
PRECIOUS STONES.
a. certain temperature upon the metallic fluorides,
chlorides, &c., themselves brought to the state of
vapour by the action of heat.
In these conditions a double decomposition is
produced, and metallic oxides are formed, which
crystallize.
Results of the same order are produced by intro-
ducing only the vapours of the metallic combi-
nations destined to give rise to new bodies.
M. Daubrée obtained by this process a great
number of species perfectly crystallized; among
them the oxide of tin and quartz. Instead of
making the vapours react upon each other, he
made them react upon. solids, and the results were
no less satisfactory. It is by the employment of
this method that M. Daubrée has produced first
the apatite, and a compound having a close analogy
to the topaz; and more lately has, by the use of
the chlorides of silicon and aluminium, produced
crystallized silicates and aluminates.
M. Durocher has obtained a great number of
crystals by a method similar to that of M. Daubrée.
The only essential differences between their pro-
cesses is that Durocher used soluble combinations.
which pertained each one to the elements of the
mineral he wished to crystallize, and Daubrée in-
terposed vapours of water as a means of decom-
posing the generating vapours.

ARTIFICIAL PRODUCTION.
231
The latest experiments in the reproduction of
crystals, and particularly of precious stones, have
been made by MM. Deville and Caron.
Caron. The
method employed by these chemists is founded
upon the same principle as those of Daubrée and
Durocher; but the agencies employed by them are
incomparably more powerful, and the results which
they have obtained more brilliant.
With the enormous température developed by
the furnaces of Deville and Caron ordinary cru-
cibles could not be used: they melted like lead.
The crucibles which they used were made of lime.
Anybody can make them, and they are absolutely
fireproof.
Among the principal results obtained by the ex-
periments of these chemists were crystals of white
corundum, rubies, and sapphires.
The crystals of corundum, nearly two-fifths of an
inch in length, exhibited all the crystallographic
and optical properties of the natural corundum.
The rubies, obtained very nearly in the same way,
had the violet-red tint of the natural ruby conveyed
to them by the oxide of chromium, which furnished
also, in a different proportion, the blue of the
sapphires. Sometimes, in the experiments of De-
ville and Caron, red rubies and sapphires of the
most beautiful blue were obtained side by side.
A similar experiment produced specimens of
232
PRECIOUS STONES.
:
cymophane identical in all respects with the cymo-
phane found in America, in small but very perfectly
formed crystals.
The processes we have just described are all dis-
tinguished by special features, though depending,
as already mentioned, on a small number of laws.
It is probable that nature has employed them by
turns. In any case they suffice to explain the for-
- mation of the greater number of crystallized mineral
substances at present known.
:
:
:

PART IX.
False Precious Stones.
"Art, aping Nature, eager to deceive,
Has learnt to imitate the jewel true
With lying glass, and thus beguile the view.
Hence hard the real gems from false to know,
When pastes with imitative colours glow.
Their boasted virtues soon as tested fail,
And hence discredit does the true assail.
Yet the true gem, by sages duly blest,
In wondrous works its power will manifest."
Under the name of false precious stones, there
are two kinds of productions which are essentially
different-the one natural, the other artificial...
The first comprehends stones sufficiently hard
to resist the file; they are generally quartz, either
hyaline or variously coloured.
The second consists of artificial compositions of
the nature of glass.
There is an intermediate order, the productions
belonging to which, if well executed, are especially
calculated to deceive, and are used to great extent
in the East Indies. They are called semi-stones,
.or doublets.
-
234
PRECIOUS STONES.
FALSE PRECIOUS STONES OF THE NATURAL
KIND.
It is of some importance to examine this subject,
because there is a prevalent belief that all false
stones necessarily have glass as their base, and are
consequently of little hardness. People often say,
when their rubies or their topazes are declared false,
"But, see, here is a file; try to scratch these stones;
you will not succeed." Very true; but submit any
piece of quartz to the same test, and the result will
be the same.
Since, as we have said, hyaline or variously col-
oured quartz is very abundant in nature, it is easy
to procure, at insignificant prices, stones that per-
fectly resist the file, and show, often in a remark-
able manner, the whole series of colours that we
admire in real precious stones.
Stones of this kind are very abundant in com-
merce; it might be said that, with few exceptions,
all those designated as occidental are of this char-
acter, and possess consequently hardly any value.
Another deception of the same kind consists in
passing off a stone of a certain nature and a certain
value, for another stone of a different nature and a
much higher value.
The colourless varieties of sapphire and topaz,
which in density, in hardness, and in refractive
FALSE PRECIOUS STONES.
235
power differ but little from the diamond, are fre-
quently cut into roses and brilliants, and sold for
diamonds. A proof of this fact is furnished by the
commercial price of the colourless topaz, which is
much greater than it could obtain as topaz. It is
valued in the secret hope that after cutting it may
be sold for diamonds.
At the present day there are means-such as the
scales for determining specific gravity, polariscopes,
&c. for distinguishing with mathematical certainty
the diamond from the sapphire or topaz; but these
tests are of modern origin; and in the middle ages
not only colourless topazes, but those whose tint
had been removed in different ways, principally by
the action of fire, frequently passed current for
diamonds. Nay more than this, under the influence
of the ideas that then prevailed concerning trans-
mutation, the successful experimenters believed
that they had actually transformed rubies and
topazes into diamonds.
Cardan furnishes some very curious details on
this subject. He gives a receipt by which “a limpid
sapphire of a faint colour" may be boiled in melted
gold and converted into a true diamond.
SEMI-STONES OR DOUBLETS.
This mode of imitating real stones, though vary-
236
PRECIOUS STONES.
ing in a great many respects, is generally effected
by giving the proper shape to a morsel of strass;
removing from the upper portion of it a certain
thickness, and replacing this by hard stone in such
a way as to complete exactly the strass stone, then
mounting the whole in a setting that completely
conceals the line of junction of the two stones.
: Doublets are of two kinds: in both the under
part is strass, but in one the upper part is a plate
of the real stone; in the other, it is simply hard
stone, generally quartz, and of no value.
The invention of this process has been attributed
to a modern jeweller of Paris, named Bourguignon;
but in reality it can be traced as far back as the
fifteenth century.
A complete description of the mode of manufac-
turing doublets is given by Cardan, who has even
preserved for us the name of the inventor:-
"A fraud of a very bad character, and one very
difficult to find out, was employed by Zocolino ——.
This venerable personage used to take a thin flake
of real precious stone, such as carbuncle, emerald,
&c., when he wished to imitate the carbuncle or
emerald, choosing such pieces as had but little
colour, and were consequently very cheap. Under-
neath he placed a piece of crystal sufficiently thick,
and united the two parts by means of a transparent
glue, in which he incorporated a colouring matter
FALSE PRECIOUS STONES.
237
in harmony with the stone that he meant to imi-
tate-brilliant red for carbuncle, green for emerald,
&c. He concealed the line of junction of the two
parts by means of the setting; and to avoid giving
rise to suspicion, he set them in gold, which was
not allowed except in the case of real precious
stones..
"In this way this magnificent workman deceived
everybody, even the lapidaries. However, the fraud
was at last discovered, and Zocolino took refuge
in flight.
"It appears that this personage had a peculiar
disposition for fraud, for he turned his attention
afterwards to the fabrication of counterfeit money;"
and ended by being condemned to death."
An examination of the objects adorned with
precious stones, that have been executed in the'
middle ages, shows that the process described by
Cardan was not unfrequently employed.
· FALSE PRECIOUS, STONES OF THE ARTIFICIAL
KIND.
The basis of all false stones of this kind is glass.
A fixed alkali (soda or potash) and silica heated
to a red heat will combine and produce glass.
Alumina, lime, magnesia, &c., may enter into the
combination with the silica; but the result in both
238
PRECIOUS STONES.
cases is colourless, or what is ordinarily called
white glass. But if to these substances metallic
oxides, or metals in a divided state, are added,
even in minute quantities, the result is coloured
glass.
Chemical analysis shows us that the elements of
glass are found in all vegetables. If, then, a fire
consumes a certain quantity of wood, gathered to-
gether at a single spot, vitrifications will be found
in the residuum. When silicious stones are sub-
jected to an intense heat, the bases contained in
the stones and in the cinders combine and produce
glass. This is what may be seen every day in an
examination of the interior walls of a lime-kiln or.
brick-kiln. It is evident, then, that the discovery.
of glass belongs to the earliest period of man's
existence. If it be remarked, besides, that the glass
thus obtained is always coloured, and therefore in
harmony with the pronounced taste of primitive
people for brilliant objects, we understand how
these vitreous substances produced by conflagra-
tions and, above all, by the action of fire upon
silicious stones, must have excited, in the most
lively manner, the attention of men from the first
ages of our species.
Had this book been written a dozen or fifteen
years ago, it could have furnished but little infor-
mation on this head; but, thanks to the researches

FALSE PRECIOUS STONES.
239
of archæologists, and in particular those of M. Bou-
cher de Perthes-for whom, no doubt, history re-
serves an exceptional place in its annals-humanity
beholds its origin almost instantaneously extended
far beyond the historic ages, far beyond all tra-
ditions! A new period, during which man lived
upon our globe, and which has not until our own
epoch been suspected, is now revealed in the most
incontestable manner; and among the remains of
human industry referable to that remote epoch,
Fig. 91.-Egyptian Bracelet in Ceramic Paste, with coloured Ornamentation.
are found objects of coloured glass. It must be re-
marked that coloured glass is much more easily
obtained than glass without colour, and that the
latter has been produced with ease only in quite
modern times.
Without departing from historic times, but only
reverting to their most ancient ages, we find that
the Egyptians understood very early the manufac-
ture of glass, and especially the coloured glasses.
The design of an Egyptian vase of blue glass,
ornamented with white and yellow, is given in Fig.
92. In quality of material, in form, in elegance of

240
PRECIOUS STONES.
ornamentation and harmony of colouring, this vase
is in no respect inferior to the best productions of
the present day, and yet it must have issued from
the hands of the Egyptian workman four thousand
years ago. In Figs. 91, 93, 94, 95, and 96, the
objects represented are of ceramic paste. From
Fig. 92.-Egyptian Vase of Blue Glass, with white and yellow Ornaments.
an artistic point of view, these objects are of
no value, but the delicacy of their details is well
worth notice, especially when we consider that they

FALSE PRECIOUS STONES.
241
must have been moulded when the matter was in
a soft state.
Fig. 93.--Egyptian Moulding in Ceramic Paste.
In the time of Pliny, the manufacture of false
stones was far advanced as a branch of industry
Fig. 94.-Egyptian Ring, with a Bezel of Ceramic Paste.
among the Romans. There existed several treatises
16

242
PRECIOUS STONES.
upon the subject; and Pliny declared that it was a
difficult task to distinguish between the false and
the true. Not only in Rome were false stones in
vogue, but, according to Pliny, the Indians coun-
terfeited jewels with success, especially opals.
The processes that Pliny was so careful not to
divulge, were not held sacred with the same scru-
pulousness by the alchemists of the twelfth and
thirteenth centuries. Both Albertus Magnus and
St. Thomas Aquinas refer openly to this subject;
Fig. 95.-Egyptian Ring of Gold, with inlaid work of Enamel.
and the latter in his treatise on the Essence of
Minerals, states explicitly that there were "men
who fabricated artificial jewels." Among the pre-
cious stones counterfeited, he instances the hya-
cinth, sapphire, emerald, ruby, and topaz.
At the commencement of the Renaissance the
fabrication of false stones still continued; but it was
not yet separated from much hesitation and experi-
ment. Cardan
Cardan proves this in his curious receipts.
A century later we perceive by the descriptions

FALSE PRECIOUS STONES.
243
of Kircher that the industry had greatly advanced.
To the unburned "brick" of Cardan, in whose cavity
his mixture for precious stones was heated, excel-
lent crucibles had succeeded; special furnaces had
replaced the brick-kiln; and in the time of Kircher,
that is to say, about the middle of the seventeenth
century, false stones were no longer manufactured
according to methods differing for each stone, but
according to a general formula much the same as
that followed at the present day.
Fig. 96.-Egyptian Moulding in Ceramic Paste.
No other proof is needed than the writings of
Kircher to dissipate the error that has ascribed the
invention of strass-a peculiar kind of glass of con-
siderable refractive power, which forms the base of
all modern artificial gems-to a workman of that
name, towards the close of the last century. This
production was perfectly well known in the middle
ages; and it was used for exactly the same purposes
as it is used for to-day-for decoration, and the
counterfeiting of precious stones. It is distin-
guished from ordinary glass by the presence of
244
PRECIOUS STONES.
about 50 per cent. of oxide of lead among its con-
stituents.
There existed in the middle ages, and probably
had existed among the ancients also, a substance
called at first amasa, then encausta, and lastly
smalta, from which last term our modern émail
(enamel) is derived. These were generic expres-
sions for substances formed of glass and a metallic
oxide; and the basis employed was certainly a
kind of strass-that is to say, glass containing a
great quantity of oxide of lead.
The improvement made in strass since the middle.
ages is due to our modern chemistry, which fur-
nishes productions of a perfect purity, otherwise
the ingredients, and probably their proportions, re-
main the same; and the same rule is still observed
that the longer the fusion is prolonged, the finer
will be the quality of the strass. According to M.
Dumas, the strass now employed consists of—
Silica,
Red oxide of lead,
Calcined potash,
•
Calcined borax, alumina, and arsenious acid,
38°2
•
53°0
7.8
Traces.
When the strass is obtained very pure, all the
precious stones may be imitated with it. For this
purpose it is melted and mixed with substances
having a metallic base, generally oxides, which,
combining with the elements of the strass, com-
municate to it the most varied colours. We add a
FALSE PRECIOUS STONES.
245
few details to show how the principal gems may be
imitated.
Diamond.-The diamond being colourless, pure
strass, cut into brilliants and roses, is used to coun-
terfeit it.
Ruby.-1000 parts strass, 40 glass of antimony,
I purple of Cassius, and I, in excess, of gold.
Sapphire.-1000 parts strass, and 25 oxide of
cobalt.
Topaz.-Same formula as that of the ruby, with-
out the excess of gold, and heated for a less time.
Emerald.-1000 parts strass, 8 oxide of copper,
and 0'2 oxide of chromium.
Amethyst-1000 parts strass, 25 oxide of cobalt,
and a little oxide of manganese.
Garnet.-1000 parts strass, and a variable quan-
tity of purple of Cassius, according to the shade to
be obtained.
Aventurine.-For several centuries Venice has
had the monopoly of the fabrication of aventurine;
and even now, it is a Venetian artist, Bibaglia, who
furnishes to commerce the artificial aventurine that
is most highly prized.
Aventurine is a glass the base of which is soda
ash, lime, and magnesia, coloured yellow by oxide
of iron, and holding in suspension a large number
of small particles of oxide of copper. The distri-
bution of these particles in a regular manner through

246
PRECIOUS STONES.
the whole vitreous mass appears to be the chief
difficulty in its manufacture.
The dexterity requisite to accomplish this must
be very difficult to attain, for the profits realized
from the manufacture of aventurine are remarkably
large. According to its quality, the artificial gem
sells for $5 to $15 the pound, while the raw mate-
rials that enter into the composition of a pound of
it are certainly not worth a quarter-dollar.
French chemists-M. Hautefeuille in 1860, and
M. Pelouze in 1865-have published processes by
which productions have been obtained equal to
that of Venice, and, in the latter case, perhaps
superior.
The new aventurine of M. Pelouze has a beautiful
lustre, and a hardness exceeding that of glass and
ordinary aventurine. It is obtained by melting
together 250 parts sand, 100 parts carbonate of
soda, 50 parts carbonate of lime, and 40 parts bi-
chromate of potassium. It will be seen that by
this formula the spangles with a basis of copper
are replaced by spangles with a basis of chrome.
FALSE PEARLS.
False pearls are little hollow spheres of glass
covered internally with a coating imitating the
orient of natural pearls. Their fabrication com-


FALSE PEARLS.
247
prehends two series of operations-the production
of the sphere, and the introduction of the coating.
The spheres are produced by the glass-blower, who
by aid of an enameller's lamp solders the extremity
of a tube having the proper diameter, and blows
into the tube when the substance is of the right
consistency. In this way very regular little spheres
are obtained, that serve for the composition of the
ordinary quality of false pearls.
In pearls of great beauty the tube employed is
slightly opalescent, and the glass-blower, besides,
gives to the little spheres, while they are yet malle-
able, certain slight perceptible inequalities of sur-
face, by gently tapping them with a small iron bar.
This gives them a yet greater resemblance to natural
pearls, which are very seldom absolutely regular.
No mention is made in ancient writers of artifi-
cial pearls being made, and it is not till we come
down to the beginning of the sixteenth century
that we find Venice had then established a reputa-
tion for this branch of industry.
At first the glass balls were filled with various
materials, generally with a base of mercury. But
in the year 1680 a rosary-maker named Jacquin
conceived the idea of using, in the place of this
mercurial mixture, a harmless substance that pro-
duced an infinitely more perfect colour.
This substance, the essence of orient, is formed

248
PRECIOUS STONES.
from the scales of the bleak or ablette, a little white
fish which abounds in the Seine, the Marne, and
the Loiret.
The fishes are rubbed rather roughly in pure
water, contained in a large basin; the whole is then
strained through a linen cloth, and left for several
days to settle, when the water is drawn off. The
sediment forms the essence of orient. It requires
from 17,000 to 18,000 fishes to obtain 500 grammes
(a little over a pound) of this substance.
The scaly substance is liable to decompose
quickly, and numerous chemical agents are em-
ployed by different manufacturers to preserve it.
These means are kept a secret, but it is known
that liquid ammonia, or the volatile alkali, is one
of the substances most commonly used.
The process of colouring the pearl is commenced
by lining the interior of the ball with a delicate
layer of perfectly limpid and colourless parchment-
glue; and before it is quite dry, the essence of
orient is introduced by means of a slender blow-
pipe. It is then allowed to dry; the pearl is filled
with wax, and, if intended for a necklace, is pierced.
FALSE CORAL.
A number of objects are made at the present day
of a composition intended to resemble coral, but

ARTIFICIAL COLOURING.
249
this imitation is by no means a success.
It is a
paste formed of marble dust and isinglass. The
colour is given by a mixture of vermilion and
minium incorporated with the mass.
ARTIFICIAL COLOURING OF HARD STONES
USED BY ENGRAVERS.
The hard stones preferred by engravers are those
which offer different tints or strongly-contrasted
colours. As these vari-coloured stones are much
more costly than stones of the same nature of a
single colour, chemistry has been applied to for
an artificial colouring; and the result is, that the
greater part of hard stones engraved at the present
day are artificially coloured.
The stone to be coloured is steeped in oil, and
notwithstanding its apparent impermeability, is
easily penetrated by the liquid. After being soaked
a certain time, it is taken out, and, however per-
fectly it may be dried, a certain quantity of the oil
always remains in its pores. It is then placed in
a capsule, covered with sulphuric acid, and heated
to boiling point: this heat is maintained until the
sulphuric acid is evolved, when the stone is with-
drawn and washed, and is found to have become
black.
If the stone is of a quite homogeneous texture,

250
PRECIOUS STONES.
the blackness will be uniform; but if, as often hap-
pens, its constitution is not very regular, the most
porous parts absorb the greater quantity of oil,
and varied effects of colouring are produced, which
furnish to the artist the desirable opposition of tints.
This operation can be easily explained. The oil
being composed of the three elements-carbon,
hydrogen, and oxygen, it follows that if the hydro-
gen and oxygen are removed, carbon remains. It
is precisely this removal that sulphuric acid effects.
Penetrating in the track of the oil into the pores of
the stone, it determines the union and elimination
of the hydrogen and oxygen, and leaves carbon
diffused throughout the stone in a state of excessive
division. It is these minute particles of carbon
that impart a definite colour to the stone.
So far as regards the colouring, this process
furnishes excellent results; but when it is asked,
Should the prepared stone be considered equal to
those coloured by nature? we must answer in the
negative, notwithstanding the opinion generally
held.
No doubt, in ordinary conditions, the fixity of
carbon is absolute, but in this case we must remem-
ber that it is in a state of the most extreme divi-
sion; and seeing that the natural porosity of the
stone is increased by the sulphuric acid, and that
porosity is highly favourable to the combination of

ARTIFICIAL COLOURING.
251
bodies, it seems to be not impossible that in course
of time the carbon may undergo a slow combustion,
and the colour of the stone be more or less de-
stroyed.
It is impossible, too, that a substance so corro-
sive as sulphuric acid should not make some im-
pression on the stone. Silica, it is true, is not
attacked by this liquid, but it is altered in a re-
markable manner; and then precious stones of the
agate class are not formed exclusively of silica,
but contain small quantities of different substances
on which sulphuric acid has a very decided effect.
The stones artificially coloured, then, may be
used with great success for works of secondary
value; but they should never be employed by verit-
able artists, who work "not for a day, but for all
time."

PART X.
Cutting. Setting. Engraving of Precious Stones.
"There is a fire
And motion of the soul, which will not dwell
In its own narrow being.".
As we have already shown in our first part,
precious stones are sometimes amorphous and
sometimes crystallized, but even in the latter case
they are almost always masked or very imperfect;
and as much of their beauty, especially that of the
diamond, depends upon what is called play of light,
it is one of the first concerns of art to remove this
mask and these imperfections.
For every species of precious stone known to us
there exists one form better suited than all others
to show to advantage the effects of the light, which
undergoes different modifications according to the
peculiar molecular constitution of the stone on
which it falls.
The artistic series of operations by which this
desirable form is attained is called the cutting of


DIAMOND-CUTTING.
253
precious stones. That of the diamond is the most
important.
DIAMOND-CUTTING.
The discovery of diamond-cutting has been very
generally attributed to Louis de Berquem, a resi-
dent of Bruges, in the year 1465; but in fact the
actual discoveries of Berquem amounted only to the
construction of a polishing-wheel, to be used with
diamond-dust, and a systematic arrangement of the
facets.
Long before his time diamonds were cut in
India and China; and the inventory of the jewels
of Louis of Anjou, drawn up between 1360 and
1368, included a number of cut diamonds. Indeed,
150 years before the advent of Berquem diamond-
cutters had existed in Paris, one of these especially,
named Herman, had made notable progress in his
art by the beginning of the fifteenth century.
The grand centre of diamond-cutting in Ber-
quem's time was the town of Bruges; but pupils of
his passed to Amsterdam, Antwerp, and Paris,
where they established other workshops for dia-
mond-cutting. Those at Paris did not at first
succeed, but afterwards, under the patronage of
Mazarin, diamond-cutting took an important posi-
tion at Paris.
After the death of Mazarin this

254
PRECIOUS STONES.
industry declined, and the revocation of the Edict
of Nantes gave it a blow which it never recovered.
At the present day Amsterdam is the head-quarters
of this industry, and Mr. Coster's establishment in
this city is the largest diamond-cutting establish-
ment in the world. The art is still carried on at
Paris, however, and also in London, and in both
cities very successfully.
Diamond-cutting has also been introduced into
America, where it is carried on in the establishment
of Mr. Morse at Boston, and more recently at New
York, by the diamond company under the direction
of Mr. Hermann.
Diamonds are sometimes met with in their natu-
ral state in the form of well-defined crystals. It
was no doubt these that first attracted men's
attention, and for a long time they were the only
ones to which any regard was paid. They are
known as "native points."
The primitive form of the crystallized diamond,
the cube (Fig. 98), is extremely rare; it hardly
occurs once among a thousand diamonds.
The regular octahedron (Fig. 99) is a little more
frequent.
The dodecahedron, either regular (Fig. 100), or
with curved edges (Fig. 101), is a frequent form; but
the most common form of all is the octahedron,
with a six-sided pyramid on each of its faces.

ETHEROND
Fig. 97. View of Coster's Establishment at Amsterdam.

DIAMOND-CUTTING.
257
As already mentioned, there is little doubt that
the first diamonds to which value was attached
were natural crystals, that is to say, octahedrons or
Fig. 98.-Cubic System.
Fig. 99.-Regular Octahedron.
derived forms; and when the cutting of diamonds
became known in the Indies, it was necessarily dia-
monds of this class that had to be operated upon.
Figs. 100 and 101.-Common Forms of the Diamond.
Accordingly, when we examine the figures of
ancient Indian diamonds given by Tavernier and
Bernier, we find that the primitive style of cutting
in India was to take an octahedron, replace one of
17

258
PRECIOUS STONES.
the points by a plane perpendicular to the axis,
treat the opposite point in the same way, but so as
to have a plane much smaller than the first, and
then cut four bezels round the principal face.
When the art of "splitting" became known, and
it was possible by this process to obtain with ease
flat-shaped diamonds of considerable size, the orien-
tals took a fancy to stones of this kind, with their
Fig. 102.-Flat Diamond of the Grand Mogul.
four upper edges bevelled down exactly like the
edges of ancient Venetian mirrors. Even at the
present day this predilection has not disappeared,
and similar stones are still those that are most
highly prized by the inhabitants of India and Ara-
bia. As an example of Indian cutting, we give a
figure of a flat diamond that belonged to the Grand
Mogul.
There are two principal forms into which dia-

DIAMOND-CUTTING.
259
monds are cut, the brilliant and the rose, both of
them subordinate, in the first place, to the thickness
of the stone. To each of these two types is attached
a number of derivative and more simple forms.
B
Fig. 103.-Natural Octahedral Diamond.
The starting point for the modern diamond, as
for the ancient Indian form, is the simple octa-
Fig. 104.
Fig. 105.
hedron. The following is the method employed in
forming the octahedron into a brilliant:-

260
PRECIOUS STONES.
In Fig. 103 let the line AB which joins the two
opposite summits, be divided into six equal parts,
and let a plane perpendicular to the line AB pass
through the second division from the upper point,
and another plane also at right angles to AB pass
through the first division from the lower point,
then a small pyramid will be detached from each
extremity, and there will remain the solid repre-
sented by Fig. 104.
Fig. 106.
Fig. 107.
These are the proportions in which the axis is
cut by the French lapidaries, but English lapidaries
usually cut five-eighteenths from the upper pyra-
mid, and one-eighteenth from the lower. The
upper and larger plane surface is called the table;
the lower is named the collet (French, culasse).
The four superior edges or ribs, and the four in-
ferior edges, are then removed in such a way that
the table and the collet are circumscribed by regular
octagons, as represented by Fig. 105.

DIAMOND-CUTTING.
261
Lastly, the eight faces which limit the table are
cut each into four facets, forming the crown; and
the eight faces of the collet are divided in the same
manner to obtain the pavilion.
The stone bears then sixty-four facets, besides
the two parallel planes-the table and the collet.
It is called the double-cut, or recut brilliant, and
being the style which best displays all the beauties
of the diamond, it is used at the present day for all
stones of fine water and of sufficient depth. Figs.
Fig. 108.-Semi-brilliant.
106 and 107 represent this form as seen both verti-
cally and horizontally.
The simple-cut brilliant has the same general
form, but it has only eight facets above and eight
below-sometimes only four-besides the table and
collet.
There is another cutting for stones whose thick-
ness is small in proportion to their surface. It is
the semi-brilliant. It consists of the upper part of a
double-cut brilliant, cut off at the line of junction
between the crown and pavilion. This form is
represented by Fig. 108.

262
PRECIOUS STONES.
THE ROSE.
In rose-cutting, the diamond is flat underneath;
the upper and convex part is covered with a vari-
able number of facets, systematically disposed
around a first, of which the summit occupies the
centre of the stone. If the stone bears twenty-four
facets it is a "Holland Rose;" if it has but eighteen
or twenty, it is a "Semi-Holland;" if the number
of facets is diminished to twelve, or eight, or even
six, it is an "Antwerp Rose."
Fig. 109.-Holland Rose.
Sometimes rough diamonds, found in the form
of pears, are covered with little facets, retaining
the general form. These stones have the name of
briolettes; they come exclusively from India, and are
generally pierced in the upper part with a very
small hole. No lapidary in Europe could drill
such a hole in these diamonds.
There are also known in commerce stones cut

DIAMOND-CUTTING.
263
into pendeloques or pendants, in the form of a half-
pear with table and collet, covered with facets on
the collet side. They are very rare, and their
price far exceeds that of brilliants of the same
weight. Fig. 110 represents one of the pendeloques
which Tavernier saw in India, and which its pos-
sessor would not part with for $11,160.
Another special form of cutting is that which was
employed for "the Sancy."
Diamonds cut in this
Fig. 110.-Pendeloque of Tavernier.
style have the form of flattened pears almost round,
of a pendeloque shape, facetted both superiorly and
inferiorly, and having a very small table above.
M. Babinet thinks that this is the form in which
both the Koh-i-noor and the Star of the South
should have been cut.
There is also the Star, invented by Caire, and
but little used. It was designed in order to take

264
PRECIOUS STONES.
advantage of certain clear portions of rough dia-
monds, which could not be otherwise used with-
out great sacrifice of material. Fig. 111 will show
the appearance of stones cut in this manner. The
form on the left represents the upper portion
of the stone; the other two figures are alterna-
tive forms in which the lower portion of the stone
may be cut.
The cutting of the diamond includes three series'
of operations: the splitting or cleaving; the cutting,
Fig. 111.-The Star invented by Caire.
properly so called; and the polishing. Special
workmen are required for each one of these
branches.¹
It is to the splitter that the rough diamond is
given; his quick penetration and ready action are
to determine the future of the stone.
First of all, he examines very carefully the little
1 The illustrations in this section relating to diamond-cutting are
taken from fine water-colour drawings sent from Amsterdam and
executed specially for this work.

BONNAFOUX
LAPLANTE

DIAMOND-CUTTING.
267
BONNAFOUX
morsel in his hand; he decides how it should be
shaped to retain the utmost weight with the most
brilliant effect; he detects every flaw and streak,
Fig. 113.-Details of a Compartment of the Splitter's Workroom.
and he knows whether the imperfections are at
the stone's surface or at its heart. Very quickly
then he sets to work. He takes a longish wooden
implement or baton, shaped so as to be con-

268
PRECIOUS STONES.
veniently held in the hand, and having at one end
a ferule extending a little beyond the wood and
filled with a mastic or cement of resin and brick-dust.
This cement he softens by heating it at a lamp, then
Fig. 114.-The Splitter.
embeds the diamond in it and lets the cement cool,
by which means the diamond is firmly fixed in its
place. With another diamond, sharply edged and
secured in the same way, he cuts a notch in the
diamond he is about to split. This notch is of a
V shape, and must lie exactly in the direction of the
cleavage-plane of the stone-a result which, though
DIAMOND-CUTTING.
269
了
​A
apparently so difficult, is easily attained by the prac-
tised eye and dexterous hand of the workman.
box beneath his work catches the dust, and a little
sieve sifts at once the diamond-powder from the
particles of resin dropped.
When the notch is cut deep enough the workman
places the wooden baton upright in a hole in a
block of lead before him; then introducing with one
hand the blunt edge of a small steel ruler into the
notch of the diamond, with the other he strikes the
ruler a smart blow with a steel rod, and the stone
is split. It is not without emotion that one sees
this blow given, for the slightest error may prove
fatal to the diamond's value for ever; but it is
given without hesitation and with perfect com-
posure.
The stone, which is now divided into two parts, is
removed from the cement; the main part undergoes
a repetition of the operation until it has received its
proper form and all flaws are removed; and the
fragments are carefully preserved to be cut into
little roses, which, however small, have a value.
In Fig. 112 a general view is given of the room
in which the splitters work in Coster's establishment
at Amsterdam. Fig. 113 shows on a larger scale
the complete arrangement of every division in this
vast workroom.
Fig. 115 is an illustration of the diamond-splitter's

270
PRECIOUS STONES.
table. The reader will see on the left the blunt-
edged steel rulers and the iron rod, somewhat in
the shape of a double cone, which serves as a ham-
mer; on the right, a saucer containing diamonds,
and supporting a pair of pincers, and a lamp; in front,
a handle having the sharp-edged cutting diamond
BONNAFOUX
CLAPLAN
Fig. 115.-Table of the Splitter.
attached, and, standing upright, the wooden imple-
ment which supports the diamond intended to be
split; in the background is a globe of water for
concentrating the light at such points as more par-
ticularly require it.
From the splitter the diamond passes to the
cutter.

DIAMOND-CUTTING.
271
At first sight the work appears to be exactly the
same as at the table of the splitter. The cutter has
two diamonds attached by cement to wooden
handles, and the same sort of a box as the splitter
has, to receive the diamond-dust. But the
But the process
Fig. 116.-The Cutter.
is essentially different. Instead of cutting a notch
in one of the diamonds, the cutter is slowly and
laboriously grinding the two together in that
mutual manner which accomplishes the smoothing
of both stones.. He is putting in practice the
famous discovery which Louis de Berquem is falsely
said to have made by chance, and, from the primi-

272
PRECIOUS STONES.
tive form received from the splitter, he is shaping
the facets of the brilliant or the rose.
The work requires great muscular force, and the
hands of the cutters have to be supported by
gloves-we might almost call them cases-of stiff
leather. These gloves are seen in Fig. 117, which
BONNAFOUX
Fig. 117.-Diamond-cutter's Table.
CLOPLANTE
represents the tools necessary to the work-table of
the cutter.
A diamond, in the hands of the cutter, has not yet
become an object of beauty; it has no lustre or
transparency, and is even more unpromising in
aspect than the rough diamond. The adamantine
lustre, which is one of its special beauties; its trans-

DIAMOND-CUTTING.
273
parency so pure; its refraction so powerful-all this
is given to the diamond in the third phase of the
cutting operation; and this phase belongs to the
polisher.
The work of the cutter is not confined to the re-
moval of the outer crust of the stones-he gives
them the definite form which they are to preserve.
If the stone is thick enough to produce a brilliant,
he forms first the table, then the collet, and suc-
cessively all the facets of the pavilion and the
crown. It is easily seen that in all this labour a
great deal of latitude is left to the cutter; but, as
the final weight, and consequently the value of the
stone, depends in a great measure on his skill, it is
only tried workmen that are intrusted with valu-
able diamonds, such as those of larger size than
four hundred to the carat. Smaller stones are
made up in lots and delivered to the workmen
after having been weighed.
So long as the diamond-cutter is engaged on a
piece of work he shuts up the stones every evening
in a little iron coffer provided with a padlock, of
which he keeps the key. All these coffers, each
with its number, are shut up after working hours in
a large strong safe, and distributed to the work-
men every morning. When the work is finished
the large stones are weighed singly, the small
stones in the lots, to see what the loss has been,
•
18

274.
PRECIOUS STONES.
and, according to the extent of this, the payment is
greater or less. If a stone is found to be wanting
in any of the lots, the workman has to pay a fine
much greater than the value of the stone. As a
Fig. 118.-General View of the Polishing-room.
COLOPLANTE
brilliant of five hundred to the carat, or still more,
a rose of a thousand to the carat, are very small
objects, it often happens that they are lost in the
course of the manipulations they have to pass
through. The floor, and the dust upon it, are then

DIAMOND-CUTTING.
275
subjected to a most minute examination, in which
a long silken broom is used.
The polishing comprehends two distinct opera-
tions-the setting, and the polishing properly so
called.
The setter has at his command a furnace filled
with burning charcoal. His work is to solder the
diamond into a quantity of alloy resting in a brass
or copper cup, which has attached to it a rod for
holding it by. The alloy consists of a mixture of
tin and lead, which, when pressed into the cup, gives
to the whole the form of an acorn, with the dia-
mond as its apex. This soldering is no easy task.
There are sixty-four distinct surfaces to be
smoothed in the brilliant, and each of these must
be properly adjusted in the burning mould. It
would seem that the fingers of the setters are fire-
proof, for it is with their fingers that they adjust the
setting of the metal around the diamond; and when,
after its manipulation, the alloy is plunged into
water to be cooled, the cloud of steam that arises
attests the painful temperature to which the hand
of the workman has been subjected.
The diamond, set as the apex of the acorn-shaped
lump of metal, which again rests in a brazen cup
with unyielding stem, is given to the polisher.
The polishing-rooms are the most interesting
apartments of the great establishments for diamond-

276
PRECIOUS STONES.
cutting, such as that of Mr. Coster at Amsterdam.
Before revolving steel disks, that are running
scrupulously parallel with the floor, and turning
noiselessly with a speed of two thousand revolutions
to the minute, are numerous workmen intent upon
their task.
Fig. 119.-The Polisher.
The eyes of these polishers seem of little use
compared with their sense of touch, which has been
exquisitely educated. It is by the instinct of their
finger-ends that the point of the diamond-kept
constantly wet with mingled diamond-dust and
olive-oil-is adjusted with determinate exactness of

DIAMOND-CUTTING.
277
position, to the face of the revolving disk. It is
clamped in a wooden rest, and the pressure is regu-
lated by leaden weights, so that the diamond just
touches the flying wheel. To the casual observer
BONNAFOUX
C.LAPLANTS
Fig. 120.-Instruments used in Polishing.
the polishing art seems to be one requiring little
skill or intelligence, but to acquire proficiency in
the work requires years of assiduous toil.
From generation to generation the trade has
been carried on, and the patient and monotonous
toil and technical skill inherited and acquired by

278
PRECIOUS STONES.
the finished workman is sure to be rewarded at
last by a glittering surface from the hardest stone.
Sometimes months, and even years, are required
for the perfecting of single stones. African diamonds
are said to be particularly hard and difficult to
polish; but, in the end, the most hopelessly resis-
tant gem yields to the indefatigability of man.
་
In Fig. 120 are shown some of the objects con-
nected with the polishing of diamonds. In the
background towards the left the polishing wheel of
steel is seen, and scattered over the table three of
the copper cups, filled with alloy. The implement
near the centre of the table, with the two upright
pieces or feet at the left end of it, is for holding the
diamond on the wheel during the operation of
polishing. For this purpose it has a kind of vice at
the end, in which the tail or stem of the copper cup
is tightly screwed, and the whole then forms a
sort of tripod, the cup which carries the diamond
forming the third foot. The nut of the screw,
and the key for turning it, are seen at the head of
the implement. Its use will be understood from
the cut showing the polisher at work (Fig. 119).
CUTTING OF PRECIOUS STONES OTHER THAN
THE DIAMOND.
All the other precious stones are less hard than
-

CUTTING OF PRECIOUS STONES.
279
the diamond, and they display besides the greatest
difference from each other in this respect. Accord-
ingly, though the processes followed in cutting them
are not very dissimilar outwardly to those by which
the diamond is cut and polished, yet the materials
made use of are very different. The wheels have the
same form and are set up in the same way, but
they are made of much softer materials, and the
powders with which they are covered are much less
hard than diamond-dust.
Disks of lead, tin, or sometimes zinc, copper, and
hard wood, are what the ordinary lapidaries use, and
instead of diamond-dust they employ emery (a sub-
stance consisting chiefly of alumina), tripoli or rotten-
stone (silica), tin-putty (bioxide of tin), and English
red (anhydrous peroxide of iron). Different wheels
and polishing substances are used according to the
kind of stone. The greater part of colourless
precious stones are cut with the leaden wheel, and
with rotten-stone well moistened. This serves to
give the first polish to all precious stones in which
silica is the principal element-agates, jaspers, hya-
cinths, &c.
The two styles most employed are the step-cut
and the smooth-cut or cabochon. When the latter
is very flat it is called the "tallow-drop." Each of
these may be round or oval, elongated or square.
The cabochon is plane, convex or concave on its
*

280
PRECIOUS STONES.
inferior side. In the latter case it is the double
cabochon.
Concave cabochons are employed for stones mo-
derately transparent, and this disposition tends to
facilitate a more easy transmission of light. Gar-
nets of a certain size are often cut in this form; and
this cutting is used especially for the adularia, the
cat's-eye, the hydrophane, and, above all, the opal.
Fig. 121.-Cutting of Precious Stones other than the Diamond.
It serves better than any other form to display the
special beauties of these different stones.
The stones cut in step or pavilion form are
generally not very thick, and there are usually more
steps or degrees on the lower than the upper side;
as on the upper part a large table in the centre is
generally reserved. Figs. 121 and 122 represent
forms given to a great number of coloured stones,
especially the emerald and the oriental aquamarine.
There are other forms, in which the stones cut
in circles or ovals have a large table on the upper
surface, surrounded with facets, which are either

MOUNTING OF PRECIOUS STONES.
281
triangular or triangular and quadrangular both. In
this case the lower face is covered with quadrilateral
facets, and has a very small table in the centre.
Fig. 122.-Forms in which Stones are often cut.
Rubies and sapphires are frequently cut very
much like the diamond, with this difference, that
there is less thickness given to their upper part.
MOUNTING OF PRECIOUS STONES.
Precious stones, which enter into jewelry in a
thousand ways, are rarely seen simply pierced and
suspended as a drop; on the contrary, they are
nearly always elaborately mounted in silver or
gold. At the present day gold is used almost
exclusively for the setting both of colourless and
coloured stones; but silver is considered more artistic
for the former, as it preserves their limpidity and
brilliancy, and even lends them additional splen-
dour, as gold does to the coloured stones.

282
PRECIOUS STONES.
There are two modes of mounting precious
stones-one, which leaves only the upper part
visible, called the close-setting; and the other,
leaving the stone uncovered both above and below,
called the open-setting.
A modification of the open-setting, called the
knife-edge setting, leaving the edge of the stone
clear, is used with beautiful effect for diamonds.
ENGRAVING OF PRECIOUS STONES.
When we examine the marvellous artistic pro-
ductions, executed in cameo or intaglio, upon pre-
cious stones, we naturally think that the means
employed must be numerous and complicated, but
in reality the apparatus and the tools of the en-
graver are as simple as those of the lapidary. They
consist of the lathe, and a series of little rods with
heads of different shapes, all of which can be ad-
justed to the lathe.
The lathe, as will be seen from the appended
figure, is a very simple affair. The axis, driven by
the belt from the wheel, is pierced at the centre
with an orifice, into which the tools for cutting the
stone are firmly fixed by means of a screw. The
engraver wets the extremity of the mounted rod
with diamond-dust made into a paste with olive-
oil, and as the wheel is in motion he applies the

ENGRAVING OF PRECIOUS STONES.
283
stone, properly prepared by the lapidary, and firmly
cemented to a piece of reed, to the revolving tool.
The diamond-dust enables the tool to cut into the
BONNAFOUX
C.LAPLANTE
Fig. 123.-The Lathe at work.
stone with ease. As the design is frequently very
elaborate and of the greatest delicacy, the tools are
necessarily multiform.
Among the different varieties there are four most

284
PRECIOUS STONES.
used. The first is hollow; it describes circles with
the utmost facility, and serves, when required, to
perforate hard stones. The second is a disk quite
blunt at the edge. The third is a sharp-edged disk
of very frequent use, serving as a saw. The fourth
is a rod, terminated by a little sphere, and is very
frequently used. Fig. 124 shows all the tools used
by the engraver.
As precious stones suitable for engraving have
always a considerable and sometimes a very high
value, it is important to be able to make use of every
portion of them. They are therefore sawn instead
of being ground down, so that the portion removed
may also be made use of. This operation may be
performed in different ways. The most ancient and
simple method consists in fixing the stone to the
extremity of a support, and cutting it by the friction
of a bow, strung with two iron wires twisted together,
and impregnated with diamond-dust. This method,
however, is both tedious and irregular, and hence
instruments, infinitely more rapid and precise, have
been substituted for the bow.
Fig. 125 represents the mill of the lapidary, with
the polishing disk replaced by a steel disk with a
cutting edge, against which the workman applies the
stone with his left hand, while he sets the apparatus
in motion with his right. The disk is sprinkled
with diamond-dust, which the workman collects

Lso
Fig. 124. – Tools and other objects used by the Engravers of Hard Stones.

ENGRAVING OF PRECIOUS STONES. 287
and keeps always supplied to the edges of the
wheel. This work is usually performed by the
lapidary, preparatory to the engraver's task; indeed,
the stone is sometimes set by the jeweller before it
Fig. 125.-Apparatus for Sawing Hard Stones.
is engraved, in which case it is embedded in cork.
If it is merely shaped and not set, it is fastened
upon a baton with lapidary's cement.
The tools and apparatus employed by the en-
graver are therefore very simple; but just as the

288
PRECIOUS STONES.
sculptor, besides his chisel and block of marble,
must have a certain amount of technical skill, and,
above all, the artistic faculty, so is it with the en-
graver in hard stones.
To execute a high-class work of art on a stone
of one colour is very difficult; but stones of different
colours, and with the colours variously disposed,
are those most commonly employed. Here the
difficulty is enormously increased, for the artist,
besides having to attend to the cutting, properly so
called, has also to compose his design, and to
observe that in working it out he takes the fullest
advantage of the different colours of the stone.
We shall give one example to show the wonder-
ful effects that are sometimes obtained by artists
when working on stones of different colours. The
design is that of a shepherd sitting on a rock with
a staff in his hand. His face, hands, and legs are
flesh colour; his coat has several holes in it through
which his shirt appears; and the artist has taken
advantage of a wood-coloured vein in the stone to
represent his staff. Beside him is a tree with some
green leaves on it, and having the trunk designed
with the utmost fidelity.
Stones on which the design is raised above the
general surface are called cameos; those having the
design sunk below the surface are called intaglios.
The stones used for cameo-cutting are generally
{

ENGRAVING OF PRECIOUS STONES. 289
•
opaque or semi-transparent, such as the onyx, sar-
donyx, cornelian, agate, &c. They are suited for
subjects of the most varied character.
Intaglios are very often executed in transparent
stones, and the subjects treated in this manner are
more limited in number. They are chiefly such as
seals, devices, coats of arms, &c.
In modern times Rome has almost a monopoly of
this class of productions, exporting every year more
than $50,000 worth of them.
In the Paris Exhibition of 1867 several magni-
ficent cameos by Girometti were exhibited. One
of these was a grand composition, representing
Ptolemy Philadelphus and Arsinoe, valued at $6000,
and executed on a superb oriental cornelian, which
alone cost $2000.
Another design was an Achilles, on an oriental
sardonyx, and valued at $2400. This was a striking
example of the skilful manner in which artists may
avail themselves of the different tints of a stone.
The face of the hero seems bronzed by the sun,
while his helmet and shield are of the colour of
steel.
19

290
PRECIOUS STONES.
NAME.
COLOUR.
GENERAL CHARACTERISTICS OF PRECIOUS STONES.
COMPOSITION.
System of
Crystalliza.
tion.
Specific
Gravity.
Place in the
Scale of
Hardness.
Refrac-
tion.
Index of
Refraction.
Dispersive
Power.
Electrical,
Pro-
perties.
Fusi.
bility.
Lustre.
Trans-
parency.
DIAMOND,
RUBY,
•
Sapphire,
TOPAZ,
EMERALD,
AMETHYST,
Oriental.
Violet,
SPINEL RUBY, Deep red,
Alumina,
White, yellow, blue, Pure carbon.
black,
Red, violet red,
White, blue, violet,
Yellow,
Green,
Cubic.
3'4 to
3'6
2'45
10
Simple. to
2'48
0'38 Positive.
In-
Ada-
Very
fusible. mantine. great.
Reten.
tive of
Alumina,
Iron and Lime,
•
98.50 Rhom-
1'50 boidal.
3'9
electri-
In-
Vitre-
to
9
Double. | 176 | 0˚026
Com-
city for fusible.
ous.
4'2
plete.
some
hours.
•
69.00
Magnesia,
26.00
I'75
BALAS RUBY,
Violet rose,
Protox. of iron,
0'75 Cubic.
3'8
8
Simple. to 0'04
None.
In-
fusible.
ous.
Silica,
3'00
1'80
Vinegar red,
Oxide of chrome.
Ap-
Vitre-proach-
ing com-
plete-
ness.
CHRYSOBERYL, Asparagus green,
Alumina,
80'00
·
CHRYSOLITE,
CYMOPHANE,
Greenish,mixed with
yellow,
Greenish yellow,
Glucina,
•
20'00
•
Traces of oxide of iron,
3
to
8'5
|
Double. 176 0033 electri-
and oxide of copper.
3'6
CAT'S-EYE,
Gray-green, with
concentric veins,
>>
Reten-
tive of
Trans-
Vitreous
In-
and a
parent
and
city for fusible.
little
semi-
several
hours.
opales-
trans-
cent.
parent.
EMERALD,
BERYL,
Aquamarine,
Green,
Bluish green,
Sea-green,
Silica,
Alumina,
Glucina,
Oxide of iron,
68'00
•
46°00
12'00
Неха- 2'67
gonal
7'5 Double,
to
to
Prism.
2'75
8
but
feeble.
1'58 0026 Positive.
Not in-
fusible.
Vitre-
ous.
Feeble.
1'00

GENERAL CHARACTERISTICS.
291
NAME.
COLOUR.
COMPOSITION.
QUARTZ,
ChrysopraSE,
OCCIDENTAL
White, smoky,
Vert-de-gris,
System of
Crystalliza-
tion.
Violet,
AMETHYST,
Brown, green,
red
JASPER,
Silica.
veins,
AGATE,
Clear gray tints,
Traces of alumina, oxide
of iron, &c.
Hexa-
gonal
Prism.
CORNELIAN,
Red, often bright
red,
ONYX,
White, grayish, and
dark brown,
Sardoine,
Fawn colour,
·
Heliotrope,
•
Specific
Gravity.
Place in the
Scale of
Hardness.
Refrac.
tion.
Index of
Refraction.
Dispersive
Power.
Electrical
Fusi-
Trans-
Pro-
perties.
Lustre.
bility
parency.
2'65
7 Double.
I'55
0`026 Positive.
In- Vitre- Trans-
fusible.
ous. parent.
OPAL,
Iridescent,
Silica, 91; water, 09'00
Not
2'11
Gray white, often
Silica,
HYDROPHANE,
transparent when
Alumina,
93'00 Crystal-
to
5'5
to
"
"
In- Vitre-
fusible. ous.
Feeble.
wet,
Water,
2'00
5°00
lized. 2'35 6'5
PERIDOTE,
•
CHRYSOLITE, Golden yellow,
Silica,
Leek green,
30'75
Magnesia,
•
50'04 Oblique
3.41
Acquir-
ing
Protoxide of iron,
9'19
Rhom-
In- Vitre- Trans-
manganese, o og
boidal
56 Double. 166
166
0033 electri-
fusible.
nickel, 0'32
Prism.
OLIVINE,
Greenish,
"
•
Alumina,
3'35 to
3'34
city by
friction.
ous. parent.
O'22
Fusible
GARNET,
Varied colour,
Silica,
Vitre-Varying
Grossularia,
Tint most esteemed,
violet red,
Alumina,
40'00
. 20'00
•
Oxide of iron, 34°00
·
ALMANDINE,
Cubic
System.
3'65 to
4'22
6'5
before ous
from
to
Simple. 1760'033
same.
the
Lime,
4'00
7'5
(See page 173).
pipe.
and transpa-
blow- slightly rent to
[resinous. opaque.
ན

292
PRECIOUS STONES.
GENERAL CHARACTERISTICS OF PRECIOUS STONES-(Continued).
NAME.
COLOUR.
COMPOSITION.
Systein of
Crystalliza-
tion.
Specific
Gravity.
Place in the
Scale of
Hardness.
Refrac-
tion.
Index of
Refraction.
Dispersive
Power.
Electrical
Pro-
perties.
Fusi-
bility.
Lustre.
Trans-
parency.
Brownish red,
HYACINTH,
Zircona,
66.00
Colourless, yellow, Silica,
•
ZIRCON,
greenish,
Oxide of iron,
34.00
traces.
Pris-
matic.
Double
4°47 75 to a high 1990'044 tric by
degree.
friction.
Is elec-
In-
fusible.
Resin-
Vitreous Trans-
parent.
ous.
Silica,
58.00
JADE,
Pale green, and olive
coloured,
Lime,
13.00
Not
Semi-
Magnesia,
•
2500 Crystal-
2'97
same.
Fusible.
""
""
"
"
Milky
white.
Oxide of iron,
2.00
lized.
transpa-
rent.
Alumina,
3'00
7'00
Tourmaline,
LabradoriTE,
TURQUOISE,
Alumina,
Lime,
Showing all the col-
aline aspect, nearly
ours from the hy-
pure, to an opacity
the most complete.
Different
colours,
upon gray ground,
Boric acid,
Silica,
Alumina,
Oxide of iron and
manganese,
Alkaline base,
Silica,
• 41'00 Rhom-
40'00 boidal.
3°07
Double.
6:00
•
8
•
5'00
55'00
28.00
Pris-
2'5 to
1'620'028
Taking
electri-
city by
friction
and by
heat.
Fusible.
Vitre-
ous.
Trans-
parent
to
12'00
matic.
2.7
Double.
opaque.
Vitre- Opaline.
ous.
Soda,
•
5'00
Alumina,
· 44'50
ish blue,
Pale blue and green- Oxide of
Phosphoric acid, . 30'90
Semi-
copper, .
4'00
2.83
to 3
6
none.
"
"
""
In-
fusible.
Vitre-
ous.
iron,.
1'50
transpa-
rent.
Water,
Silica,
19'00
49'00
Alumina,
II 00

:
NOV 29
MAY 3 1/1951
› 030
DEC
DEC 15
DEC
Dat
JUN 28 1971
5 1976
JAN

UNIVERSITY OF MICHIGAN
3 9015 03344 6967
The But with a west out t