A 57181 6
MOTED
ND
ARI
QE
392
J47
1871
गु

OF
University of
Michigan
Libraries
1817
ARTES SCIENTIA VERITAS






A
TREATISE
ON
DIAMONDS AND PEARLS,
IN WHICH
THEIR IMPORTANCE IS CONSIDERED,
•
AND
PLAIN RULES ARE EXHIBITED FOR ASCERTAINING
THE VALUE OF BOTH;
AND THE
TRUE METHOD OF MANUFACTURING DIAMONDS.
BY DAVID JEFFRIES,
JEWELLER.
The Fourth Edition, corrected to the present time.
LONDON:
W. L. MOLYNEUX, 127, STRAND.
MDCCCLXXI.
Price-Subscribers, 7/6; Non-subscribers, 10/6.
Science Library
1
QE
33%
J4.7
1871
Science
Mineralogy
Wormse
5-18-52
79192
ORIGINAL DEDICATION.
TO THE
KING.
I
SIR,
BEG leave, with the profoundest humility, to
dedicate the following Treatise to your Majesty,
the patron of truth and friend to the common in-
terests of mankind, more particularly to that of
your Majesty's subjects; in which your royal
character shines with the brightest lustre.
1
iv.
ORIGINAL DEDICATION.
It contains rational and plain rules for estimating
the value of Diamonds and Pearls under all circum-
stances, and for manufacturing Diamonds to the
greatest perfection: both which have hitherto been
but very imperfectly understood. From hence, all
property of this kind has been exposed to the
greatest injury, by being subject to a capricious.
and indeterminate valuation; and the superlative
beauty of Diamonds has been much debased.
To countenance a work calculated to promote a
general benefit, it is humbly apprehended, will not
be deemed unworthy the condescension of a crowned
head, as these jewels constitute so large a part of
public wealth; and, as they are, and have been,
in past ages, the chief ornaments of great and
distinguished personages in most parts of the
world.
ORIGINAL DEDICATION.
V.
That the supreme Disposer of all things may long
preserve your Majesty, the guardian of the com-
merce and properties of these your kingdoms, and
that you may continue to reign in the hearts of a
grateful and loyal people, is the fervent prayer of
May it please your Majesty,
Your Majesty's most dutiful,
And most faithful Subject,
DAVID JEFFRIES.

:

TO THE READER.
AS the following Treatise is calculated to inform
the world concerning the value of Diamonds
and Pearls; the weights made use of relative
thereto, are here previously explained, as the
knowledge of them will be found necessary to the
public. They agree the nearest to troy weight of
any other, and are commonly called carat weights;
150 carats make about an ounce of that weight.
Carats are divided into halves, quarters, or grains;
eighths, sixteenths, and thirty-two parts.
as
The draughts of the sizes of Brilliant and rose
Diamonds, exhibited in the plates, are tests to
prove the truth and defects of the manufacture of
any Diamond, and will be found as necessary
scales and weights, in attaining to a right judg
ment of their value. To make the truth of this
assertion appear more evident, it is here to be
observed: first, that either a Brilliant or rose
Diamond may be wrought in such a manner as to
3.
viii.
TO THE READER.
contain one-fourth, or even one-third, more weight
than it ought to have, which necessarily injures
the beauty of its form, and likewise injures its true
spirit and lustre ; and, if that over-weight be
injudiciously valued, together with its due weight,
the price will be thereby greatly heightened above
its just value, more especially in large Diamonds.
All which over-weighted stones will easily be dis-
covered by the sizes exhibited in the plates, which
exactly show the true expansion of well-wrought
Diamonds.
Secondly, it is to be observed, that the sizes
before referred to will discover if any stones do not
carry their true substance; an important circum-
stance to be regarded, inasmuch as any degree of
want thereof necessarily lessens the spirit and
lustre they would otherwise be possessed of. In
both cases directions are given in the Treatise, in
what manner every such stone is to be valued, as
well as all other well-proportioned ones, according
to their water, and several degrees of perfection or
imperfection, of what size or weight soever.
POSTSCRIPT.
THE price of this book, I hope, will not be thought
too large when the following matters are taken
into consideration.
First, that of its being calculated to settle the
value of Diamonds and Pearls, on a rational and
firm basis: a circumstance of no small concern, in-
asmuch as their worth has hitherto been rated by
fancy and caprice, which has frequently proved very
injurious even to traders in them, as well as to
others who have bought them for their use.
Next, as the subject concerns only persons of
rank and fortune, and those of the trade for whose
use the book is principally designed, the sale of it
is not likely to be very large. To this may be
added, that what it contains is the product of many
years' study, and difficult labour of various kinds,
attended with an expense much beyond what can
readily be imagined.
·
X.
POSTSCRIPT.
And here I shall take leave to observe, that
inasmuch as the tables of the prices of Diamonds.
and Pearls answer the same purposes in attaining
to the knowledge of the value of these jewels, as
scales and weights, they may be considered in the
same light; and that the Diamond sizes may be
depended on for their truth, they are all engraved
by myself, not daring to trust that performance to
any one else; which is likewise the case in respect
to some other things that I shall not here par-
ticularise; all which have engrossed my thoughts
and time to the neglect of my private concerns; by
that means I have greatly injured a fortune (not got
by trade) that put me above entering on this work
with any mean lucrative views, and least of all, that
of publishing for the sake of the profit that might
arise therefrom. On the contrary, my former cir-
cumstances enabled, and my inclinations led me to
engage in this attempt, in order to serve the public
and the jewel trade. And to my great satisfaction,
I find the principles of the book begin already to
operate; from whence it may be presumed they will
more and more, and that the world will experience
POSTSCRIPT.
xi.
their utility. That this was my original motive is
a fact well known to some, and that I formerly in-
tended to have published the matters contained in
this Treatise, without having any regard to the
profit arising thereby. These circumstances, doubt-
less, will have their due weight in accounting for the
price of the book.
And now I think it my duty to mention, that
whatever knowledge I may have acquired by ap-
plying my thoughts and time this way, I shall
endeavour faithfully to employ in any business that
I may be honoured with in the jewellery trade.
This I have not spoken of in my former edition,
nor should I now, if I were not countenanced in so
doing by some persons of rank, and many of my
particular friends, both which have of late favoured
me that way, and this leads me to hope for an
increase thereof, which I flatter myself will not be
found disadvantageous to any that may engage me
in their service. In saying this, I am not appre-
hensive of having said too much.
་
CONTENTS.
Introduction
Of the production of Diamonds, and the
principle of valuing them.
Of Brilliant Diamonds, and the method of
manufacturing them.
Of the sizes or expansion of Brilliants.
Of the use of the Brilliant sizes in dis-
covering ill-wrought ones.
Of the method of manufacturing and valu-
ing Spread Brilliants.
Of Rose Diamonds.
Of the impropriety of transforming well-
wrought Rose Diamonds into Brilliants.
PAGE.
17
I
4
IO
I I
14
16
Of the form of a Rose Diamond.
Of the manufacture of a Rose Diamond.
17
19
20
.
i
xiv.
CONTENTS.
Of the sizes of Rose Diamonds, and their
use in discovering ill-made ones.
Of the method of manufacturing and valu-
ing Spread Rose Diamonds.
Of the first method of valuing wrought
Diamonds, in conjunction with Rough
Diamonds, out of which they are sup-
posed to be wrought.
Of the second method of valuing wrought
Diamonds in conjunction with the
Rough Diamonds, out of which they are
supposed to be wrought.
PAGE
21
22
24
30
Of the method of valuing
Rough Diamonds.
wrought
Diamonds, exclusive of any regard to
Of the highest and lowest prices of Rough
and Polished Diamonds.
Remarks on Brazil Diamonds..
32
35
38
Of the Table of Prices of Diamonds.
51
Of the innate perfections, imperfections and
Water of Diamonds.
55
Of the superior worth of Diamonds over all
other Jewels.
57
Reasons for working Diamonds in a com-
plete manner, and the consequences
resulting from a contrary practice.
58
CONTENTS.
XV.
Of the use of the sizes in purchasing
Rough Diamonds.
Remarks on the Indian manufacture of
Diamonds, and their custom in regard
to Rough Diamonds.
Some accounts of authors who have here-
tofore treated of Diamonds and Pearls,
and the improvements which have been
made since their time.
PAGE
65
67
72
Of Pearls, their perfection and imperfec-
tion.
75
Of the rule of valuing Pearls.
Observations on the losses supposed to be
sustained by the purchase of Jewels.
Conclusion.
78
86
92
·
INTRODUCTION.
IAMONDS and Pearls being, of all Jewels of the
DIAMONDS
greatest importance to this and most nations of
the world, justly demand the highest regard of any,
inasmuch as they constitute the largest share of
wealth of this kind, and are the chief ornaments of
great and distinguished personages; more especially
Diamonds, as being the most beautiful and valuable
of all. On which account, as I have been about
thirty years a considerable trader in them, and the
xviii.
INTRODUCTION.
•
manufacturer of Diamonds, I have studiously em-
ployed great part of my time in search of rules, to
ascertain the value of both, under all circumstancès,
whatever be their weight and magnitude; and,
likewise, for manufacturing Diamonds to the
greatest perfection. And apprehending that I have
fully succeeded-for the promotion of the commerce,
and for the benefit of the public, I have exhibited in
this Treatise, means by which the inquisitive may
attain to a right knowledge in these matters; and
more especially concerning those from one carat.
weight to those of one hundred carats.
The plates of the sizes of Diamonds, and the
tables of the prices of both, are extended no farther
than to Diamonds and Pearls of that weight. They
might be carried on ad infinitum; and the rule of
valuing will hold good, though they should weigh as
much as Governor Pitt's Diamond, purchased by the
Regent Duke of Orleans for Louis the Fifteenth,
then a minor, which weighs 136 carats; or, as three
others mentioned by Monsieur Tavernier, in the
second part of his voyages, page 148, English
translation, viz.: that of the Great Duke of Tuscany,
INTRODUCTION.
xix.
which weighs 139 carats; or that in a Merchant's
hand, which weighs 242 carats; or that of the
1
Great Mogul, which weighs 279 carats.
9
T6
If what is contained in this Treatise be found
true, it will confute the notion that some Diamonds
and Pearls are inestimable, on account of their ex-
traordinary magnitude; which, to this time prevails,
upon the supposition that no methods can be found
to determine their value, and will likewise greatly
contribute to support the dignity of the Diamond
manufacture.
PREFACE
TO THE
PRESENT EDITION.
;
THE value and importance of this work have for
many years been readily acknowledged by all in
any way interested in the subject of which it treats.
The first edition was published in 1750-more than
one hundred and twenty years since-and from that
period, no Treatise of importance of a similar kind
has appeared. The author, well versed in all matters
appertaining to precious stones, expended years of
study in maturing his plans, and after considerable
labour and expense, the work was issued. It has
always been considered as the highest authority, as
regards the value of Pearls and Diamonds; and,
although time has caused various changes, it will
xxii.
PREFACE.
nevertheless, even now be found deeply interesting,
as well as useful to all engaged in the trade.
This Treatise has long since been out of print,
and many persons having expressed a desire to
possess a copy, it has been re-printed in its entirety,
the tables, diagrams, and plates being exactly the
same as in the original edition. The lapse of time
has naturally led to many changes in prices, &c.,
thereby necessitating careful revision; and emenda-
tions, to suit the present value of Diamonds, have
been given in the notes at the foot of the pages, so
that the past may readily be contrasted with the
present. This will render the work useful as well
as valuable for all trade purposes.
The recent discoveries of Diamonds in the South
of Africa have created a great sensation at home as
well as abroad, and the question has been raised as
to the future value of these precious stones. The
hidden wealth so unexpectedly brought to light is
not sufficiently large to cause any material dépreci-
ation in value, nor do the gems found in the valley of
the Vaal, as a rule, possess the purity and brilliancy
of those discovered elsewhere, consequently it may
PREFACE.
xxiii.
safely be asserted that many years will pass away
before any influence can be brought to bear upon
the value of these precious stones.
The production of this volume has entailed much
labor and expense, and the original price has there-
fore been adhered to, as it is probable that the
demand for it will be limited. The book will always
possess a singular value, from the fact of its being
the only one of the kind published, and that for
nearly a century and a quarter no one of any note.
or experience in such matters has been found
willing or able to give to the world any work on
this intricate subject that can be deemed in the
slightest degree reliable for trade purposes. Great
honour, therefore, rests upon the memory of
David Jeffries.
THOS. WEEKES HOLMES,
Editor of the "Goldsmith.”
A TREATISE
ON
DIAMONDS AND PEARLS.
Of the Production of Diamonds, and the
Principle of Valuing them.
THAT rules may be given for the just valuing of
Diamonds, according to their increase in size
and weight, is reasonable to suppose, from this con-
sideration, that Nature has produced in times past,
as well as it does at present, Diamonds in the follow-
ing manner :-viz., a vast number of small ones, and
progressively a less number of larger, and that they
promiscuously inherit the same properties and share
alike of perfection and imperfection. This, there-
fore, is a sufficient foundation for rules to be given
for valuing them, in proportion to their size and
weight, which will be found hereafter exhibited, and
B
2
A TREATISE ON
if the use and application of them were conformable
to the production of Nature, the rules thus founded
and prescribed would never be interrupted; and
therefore, if the humour of the world demands, at
any time, more or less of any particular sizes and
weights than Nature provides, the price obtained
thereby must be reckoned the occasional, and not
the just price, and complied with as such; which
happens to be the case at present, by the extra-
ordinary use of small Diamonds in the decorations
now fashionable in jewelling; and as the price of
these small Diamonds will always fluctuate by the
alterations of fashions, little regard will be had in
this treatise to any under the weight of one carat.
It may be also observed, that the value of Dia-
monds from two to three carats, and also of polished
Diamonds, from one to one-and-a-half, do not cor-
respond with the rules hereafter laid down, the price
at present being lower than what is asserted by the
rules, which is acknowledged, and will remain so,
as long as the humour prevails of supplying the
place of Diamonds of that weight by means of sett-
ing small stones in a cluster in their room, for the
sake of a showy and flashy appearance, at a less
price than stones of these sizes would admit of; by
which means these sizes are less used than formerly
and become cheaper (the production of Nature being
always the same), and from hence they are depre-
ciated in their value, so that the present prices of
DIAMONDS AND PEARLS.
3
these sizes must also be reckoned the occasional
and not the just price.
The rules are, nevertheless, just, uniform and
consonant to Nature, and therefore are here proper
'to be offered, in order to assist in coming at the true
knowledge of the value of Diamonds of a higher
worth than such as are liable to be affected in their
price by the alteration of fashions in jewelling.
The principal rule is, that the proportional in-
crease or value of Diamonds, is as the square of
their weight, whether rough or manufactured. For
the explanation whereof, an instance is first given in
rough Diamonds, on which account it will be neces-
sary to lay down a general price, which is supposed
to be £2 per carat, meaning the whole species, good
and bad blended together, which are worthy the ex-
pense of manufactory. For example, suppose the
value of a rough Diamond of two carats, at the rate
of £2 per carat should be required, the rule is first
to multiply 2 by 2, which make 4, the square of its
weight; then multiply the product of 4 by £2, the
price of one carat, that makes £8, which is the true
value of a rough Diamond of two carats.*
* The value of a Diamond depends upon its size, colour, and
form of crystals. The rough Diamond is estimated at half its
weight, allowing a loss of fifty per cent. in cutting and polish-
ing, the process of cutting averaging from 16/- to 20/- per carat.
It will be seen that the prices have greatly increased since the
days of Jeffries, the value of stones under two carats in weight
varying from £2 15s. to £5 5s. per carat.
4
A TREATISE ON
To make this rule applicable to manufactured
Diamonds, it will be necessary to ascertain what
waste or loss of weight will be sustained in manu-
facturing them. And here it may be advanced as a
matter of fact, that half the weight will be lost; con-
sequently, doubling the weight of any manufactured
Diamond renders the rule of the same use to show
their value. This loss is to be understood to relate
to the general manufactory of brilliant and rose
Diamonds in the most perfect manner. To that
end rules are to be offered for a general practice in
both kinds of manufactory, which, if conformed
to, will be found to exhibit Diamonds in such a
manner as to be productive of greater perfection
and saving of weight, than any other standards of
practice.
Of Brilliant Diamonds and the method of
manufacturing them.
BRILLIANTS are first to be considered; and the
manufactory of a square one is fixed on for the
* The rule laid down by Jeffries, to ascertain the value of
Diamonds will not apply at the present time. The approximate
value of stones of less than five carats, depends more upon
their purity and lustre, than their size and weight. A perfect
one-carat stone is now worth £18, but one of five carats would
be about £320. Now to follow out the plan of valuation
adopted by the Author of this work, the worth of a five-carat
stone would be £450, which, however correct it may have been
in his time, does not now apply. The fact must not be over-
looked, that the value of all precious stones is regulated by the
supply and demand, and that fluctuations in prices must inevit-
ably occur according to circumstances.
DIAMONDS AND PEARLS.
5
fundamental and governing rule of practice, Nature
for the most part directing thereto, as it produces
abundantly more apparent six-pointed stones than
stones of any other form; and because the same depth
or substance, and the same manner of proportioning
that substance, which are essential in rendering a
square Brilliant of any other shape complete; and
more substance, and any other manner of propor-
tioning will be found, upon experience, prejudicial
to the beauty of their form, and the true dignity of
their spirit and lustre, compared with such as are
made conformable to the following rules:-
The form of a six-pointed rough Diamond is pre-
viously to be described, as the shape of it is not
much known.
It is a figure composed of two square pyramids,
joined at their bases, and which form an outline of
a true square. The whole figure is composed of
eight triangular faces or planes; four above the
base, and four below it, all meeting in two points,
one at the top, the other at bottom, terminating in
the poles of the axis, or line passing through the
centre of the stone from top to bottom. Some stones
are found to answer this figure very nearly. To
make a complete square Brilliant from such a stone,
if it be not exactly true to Nature, it must be made
so by art.
The first thing, therefore to be done, is to reduce
that part representing the base of the two pyramids
6
A TREATISE ON
to an exact square, which forms what is called the
girdle of the stone; and then work by the square
from the girdle, which will produce the two points
of the axis, and if it be truly executed, the length of
the axis from point to point will be equal to the
breadth of the square from side to side. A draught
of a side-view of such a stone, will be found in the
first Plate No. 1.
18
18
The next thing to be done is to produce the table
and collet; in order to which, divide the block into
eighteen parts from top to bottom, and then take
away from the upper part, and from the lower part
This gives the upper part or table side above
the girdle, which is of the remaining substance;
and the lower or collet side or, only 12 of the
original parts being left in depth. And thus the
table and collet are formed, which will be found to
bear this proportion to each other, viz., the collet
will be one-fifth, the breadth of the table. In this
state it is a complete square table Diamond.*
3
18
Its different parts are denoted by the letters a,
b, c, d, e,—a shows what is usually called the table
of the stone, which is an horizontal plane at the
*This species of manufactory has been exhibited, says Jeffries,
time out of mind, and the Brilliant which is an improvement
upon it, has been introduced during the last century, as will
appear to those who shall give themselves the trouble of an en-
quiry. But this not being essential to the present undertaking
(which will be pursued with the utmost brevity), an historical
account of these matters is omitted.
DIAMONDS AND PEARLS.
7
top; b, the upper sides or bisils; c, the girdle which
shows its expansion; d, the undersides or pavilions;
e, the collet, which is a small horizontal plane. The
pricked lines above the table, and those below the
collet, show what has been taken away.
view of one will be found in Plate 1,
σ
No. 2.
A side
This is the foundation of a square Brilliant, and
in order to render it a perfect Brilliant each corner
must be shortened part of its diagonal, and then
the corner ribs of the upper side must be flattened,
or run towards the centre of the table one-sixth less
than the sides, and the lower part which terminates
in the girdle, must be of one side of the girdle,
and each corner rib of the under side must be flat-
tened at the top to answer the above flattening of
the girdle; and at the bottom of each side of the col-
let. A side view of one will be found in Plate 1, No. 3.
The parts of the small work which complete it a
Brilliant are called star and skill fassets, and are of
a triangular shape.
Those which join to the tables are the star fassets,
those which join to the girdle the skill fassets.†
* The plan here laid down as to the form into which rough
Diamonds are cut is still adhered to very closely, notwithstand-
ing the time that has elapsed since the description of the
modus operandi was written. It must, however, be remarked,
that the double cut Brilliant is now the most common form,
and is most generally admired.
† Facets. The original mode of spelling various technical
words has been strictly adhered to. It will also be noticed
that "culet" is spelt collet.
8
A TREATISE ON
Both of these partake equally of the depth of the
upper sides from the table to the girdle, and meet
in the middle of each side of the table and girdle,
as also at the corners, and thus they produce regular
lozenges on the four upper sides and corners of
the stone. The triangular fassets on the under
sides joining to the girdle must be half as deep
again as the above fassets to answer to the collet
parts; that is to say, in the proportion of three to
two. A draught of a Brilliant rendered complete
will be found in Plate 1, No. 4.
Under the before-mentioned draughts are repre-
sented four complete Brilliants in an horizontal view,
by double draughts, weighing 36 carats each. No.
5 is a square, No. 6 a round, No. 7 an oval, No.
8 a drop. The left hand draughts regard their
upper parts, and those on the right their under parts,
which are supposed to be divided at their girdles.
They are thus separately represented, the better to
show their whole work, and in what manner it should
lie; and likewise their size or expansion, and the size
of their tables and collets.
Their perpendicular depth from table to collet, are
shown by the length of the bars placed under each
double draught. The octagon in the middle of the
left hand draught of No. 5 is the table, which is an
horizontal plane or face at the top, and is denoted
by the letter a. The triangular fassets adjoining
to the table are star fassets, and are denoted by the
!
;
DIAMONDS AND PEARls.
9
letter b. Those adjoining to the extreme part or
outlines, are skill fassets, and are noted by the
letter c. These meeting in the middle of the upper
sides and corners of the stone, form figures of a
lozenge shape round the upper sides and corners
of the stone, and are denoted by the letter d. The
outlines of this, and that of the right-hand draught,
are the girdle of the stone, and are denoted by the
letter e.
The triangular fassets adjoining the out-
lines of the right-hand draughts, are the under skill
fassets, and are denoted by the letter f. The lower
sides are denoted by the letter g. The octagon in
the middle is the collet, which is denoted by the
letter h, and is an horizontal plane or face at the
bottom of the stone. This description serves as an
explanation of the other three double draughts. All
lines within the outline of the draughts are called
ribs in Diamonds. These draughts, with these
explanations, will always be found of use to give a
right idea of a Brilliant Diamond.* In Plate 4
there is a draught of an instrument, useful for
examining the size and depth of any Diamond,
called a prover.
* No change has since been made in the method of forming
the stone. The first part of figure 5, Plate 1, gives a front
view of a double cut Brilliant, the second part of the same
figure shows the back view of a similarly cut Brilliant. The
diagrams generally will be found not only useful but accurate.
B2
IO
A TREATISE ON
IN
Of the Sizes or Expansion of Brilliants.
N Plates 2, 3, 4, and 5, is exhibited a list of the
draughts of the horizontal representation of 55
square Brilliants, from one carat weight to a hundred .
carats, ranged in progressive order, according to their
increase in size and weight, which are so many tests
to prove the truth or error of the manufacture of any
brilliant Diamond. Here it is to be observed, that
their depths are expressed by the length of the bars.
placed under each draught, and the size of their
collets by the octagons under the bars, in order more
distinctly to discern their several parts. The numeri-
cal figures on the left hand of each draught regard
their number, those on the right hand their weight.
The reason why the number of sizes is not more
multiplied is, lest the progression of increase in size
should not be discernable, and by that means should
create too great difficulty in adjusting the degrees
in which any stone departs from truth. And this
the rather, on account of other stones differing in
their shapes at the table, girdle and collet, from those
of square Brilliants, which increases, in some mea-
sure, the difficulty of determining any difference to
a great nicety; the use of the sizes being to expose
any considerable or gross departure from truth, and
to prevent the carrying on the base and heavy
manufacture, which has of late prevailed in an ex-
travagant degree, to the great disparagement of the
DIAMONDS AND PEARLS.
II
Diamond species; and has contributed, likewise, to
a great deception and imposition on the public. It
may with truth be said, regarding small stones.
(which means stones under the weight of a carat),
that, in general, they are so ill made, as to be void
of their true beauty in all respects; and by reason
of their closeness or want of due expansion, they
will not fill up, by one fourth, the same space as
well-made stones do in a piece of jewelling work.
Consequently, they are so much less in appearance,
and as they retain one-fourth more weight than
well-made stones of the same expansion, and as
they are wrought for one-third or half the price, the
vendor of such can afford to sell them at least 30
per cent. less than he can afford to sell well-made
stones. The truth of these matters will evidently
appear by future enquiry and observation.
Of the Use of the Brilliant sizes in discovering
ill wrought ones.
HERE it may be proper to show how far this ill
manner of working before-mentioned, may de-
base Diamonds of larger sizes, and how much it may
contribute to the deception both of buyer and seller.
To that end will be shown the use of the sizes in
12
A TREATISE ON
discovering a well or an ill-made Brilliant. For ex-
ample, suppose two stones of six carats weight each,
the one a well-made, the other an ill-made stone:
the first will tally in all circumstances with No. 20
of six carats weight, and the last may be loaded
with undue substance, by which means its expansion
may not exceed one of five or four carats weight.
If any Brilliant be so circumstanced, it is to be
valued only as it agrees with any of the same expan-
sion in the list, allowing for the expense of rectify-
ing; because, whatever substance or weight it carries.
beyond what its size demands, destroys in propor-
tion to such excess the beauty of its make, and its
true spirit and lustre. And here may be seen the
difference it would make to a purchaser, who may be
induced to give the price that a well-made stone of
six carats weight demands, for one whose expansion
may not exceed that of five or four carats weight.
For example, a stone of six carats weight, by the
rule laid down is worth £288; one of five carats,
£200; one of four carats, £128. If the difference
be so great in the instance given, how much greater
must it be in regard to stones of larger weights, and
as that may be easily known by the same method
of enquiry, no other instance need be here given.
Since then, so great a deception may arise from
the ill-manufacture of Diamonds, the great use of
the sizes in discovering such evidently appears.
And as the attaining a right knowledge of the true
DIAMONDS AND PEARLS.
13
make of Diamonds will be found, of all other cir-
cumstances, the most necessary in arriving at their
value, some remarks are here made, by which the
reader is informed in what manner the defects of
ill-made Brilliants will appear. To that end, an in-
stance is given of a stone, six carats weight, which
is but of the expansion of one of five carats. It will
partake, more or less, of all the following defects:
either it will be deeper than a stone of five carats,
or if not deeper, its table and collet will be larger,
and that will render it blocky, by the sides being too
upright, or it will be left too thick at the girdle, be-
fore the small work (which means the star and
skill fassets) is performed; and if such thickness
be sufficiently reduced, that is, so as to be consis-
tent with safety in setting, the skill fassets will be
executed in an obtuse or blunt manner, and that will
cause an undue swelling in the stone, or it may,
after all, be left too thick at the girdle.. A stone thus
made will unavoidably be of an ill form, and be
rendered lifeless and dull, which cannot be rectified
without the loss of its superabounding weight, which
will reduce it to five carats; and, therefore, it is to
be valued only as one of five carats. And in case
a stone, weighing six carats, should tally only in
size with one of four carats, these defects will be
proportionately increased, to the still greater pre-
judice of the stone, and therefore it will be purchas-
ing deformity at the price of beauty.
14
A TREATISE ON
Of the Method of Manufacturing and Valuing
Spread Brilliants.
CONCLUDING it unnecessary to add anything
farther on the head of full-substanced and over-
weighted Brilliants, the next thing that requires notice
is the method of manufacturing and estimating spread
Brilliants. And as to the method of making them,
to do it in the most complete manner, they must be
proportioned, as in the case of full-substanced ones,
at the upper or table side, and at the under or col-
let side, and whatever be the diameter of their tables,
that of their collets must be thereof. The small
work is to be performed in the same manner as is
practised in full-substanced stones. This is all that
is necessary to be taken notice of in regard to their
manufacture. But, previous to the method of valu-
ing them, the following observations may be sug-
gested, that as sufficient reasons have been given
to make it appear that Brilliants may be injured in
their shape and true beauty by a super-abounding
of weight, so, on the contrary, it will appear, that if
they do not carry their true or full substance, they
will be injured in both these circumstances, by re-
flecting on the consequence of rendering them very
thin or spread, which has frequently been carried to
so great an excess as to deprive them of the benefit
of workmanship, for the work must necessarily be
so flat as to cause such stones to be faint and languid
DIAMONDS AND PEARLS.
15
in lustre, and thereby less worthy of esteem in pro-
portion to such excess. Notwithstanding which, it
will be found, that in past times, instead of valuing
the weight of such wrought Diamonds less on that
account, it has been valued the more, merely for the
sake of their making a showy appearance. To which
may be added, that all such stones are more liable
to receive injury by blows, falls, or hard pressure,
than full-substanced ones.
Here it is necessary to explain what is meant by
excess, because it must be allowed, that some stones
are so formed by Nature as not to be capable of
being manufactured by art into any other than spread
Brilliants, without too great a waste of the Diamond
species. Therefore, it may be laid down as a fit
rule to include under that denomination (viz. of
excess) all spread Brilliants expanded beyond the
size of full-substanced ones of double their weight,
and such are to be valued only as they may be sup-
posed to weigh if reduced to this standard.
It remains to show in what manner spread stones
are to be valued; which is as full-substanced ones
are of the same weight similar in all other circum-
stances; and they are to be so valued, on account
of their expansion to the degree above mentioned,
for it must be admitted, that the spaciousness of
their appearance to that degree counter-balances
the deficiency of lustre, owing to their want of sub-
stance. And this is all that can be offered in justifi-
#
16
A TREATISE ON
cation of so valuing them, which carries the appear-
ance of partiality rather in their favor than disfavor,
especially in regard to such as are of the greatest
expansion within the limits mentioned, considering
that full-substanced stones have all the advantages
that both Nature and art can bestow.
Of Rose Diamonds.
HERE it is to be observed, that nothing can more
perpetuate rose Diamonds in the esteem they
have hitherto had in the world, than maintaining the
truth of their manufacture. Nor was it ever more
fit to be recommended than at present, on account
of the corrupt taste that has of late prevailed, in
converting rose Diamonds into Brilliants, under
pretence of rendering them, by that means, a more
beautiful and excellent jewel. This has frequently
been done, to the great prejudice of their value, by
lessening the weight and expansion they bore in
their preceding state, and they have frequently been
* Rose Diamonds derive their title from the peculiar form
in which they are cut, and being manufactured from pieces of
what is termed "rough," are far less expensive than Brilliants.
The rose cut Diamond possesses very lustrous qualities, indeed
far more so than the stones termed spread Brilliants. Many of
them are so minute that from 1200 to 1500 are required to
make one carat. They can be formed into very attractive
articles, and are again becoming somewhat fashionable, after
having for some years fallen into disuse.
DIAMONDS AND PEARLS.
17
:
more injudiciously manufactured in the new species.
than they were in the old. This will appear to
have been often the case, by the upper part of such
stones- not carrying a true proportion of the sub-
stance of the stone: which, of course, renders the
upper part flat, and the table of an immoderate ex-
tent; so that the side work or bezil, appears but as
a narrow border. This method of working has been
introduced for the sake of preserving the expansion
and weight of such stones, which unavoidably would
be more reduced if they were allowed their true
proportion of top; which reduction, both of their
weight and expansion, will appear ever necessary
to be done, to render such stones complete spread
Brilliants, for such only are they capable of being
manufactured into.
Of the Impropriety of transforming well Wrought
Rose Diamonds into Brilliants.
ROM what has been observed it will appear, that
FROM
no Rose Diamonds are proper subjects of this
metamorphosis, but such only as are over-weighted;
* Rose Diamonds no longer enjoy the same amount of favor
they once did, and for many years past have been regarded as
unfashionable. The cost of rose Diamonds is about half that
of Brilliants, so that for purposes of display they are more
economical, and have, consequently, found favor latterly among
those who desire to make the greatest show at the least pos-
sible cost.
E-
18
A TREATISE ON
and of such those are the most proper subjects of
the metamorphosis which have the base or gir
dle too thick. The over weight will be discovered
by the sizes hereafter mentioned. To convert any
Rose Diamond not so circumstanced to a Brilliant,
will be shown to be a practice not founded in reason,
and which carries in it the appearance of an attempt
to depreciate this ancient and spacious manufacture
of Diamonds, in order to exalt a new one beyond its
real and true merit.
For it will be found that a complete Rose Dia-
mond will be more expanded than a complete Bril-
liant of the same weight, and proportionably so in
regard to spread stones; therefore, as it has been
shown that an increase of expansion is substituted
in the room of depth or substance in Brilliants, the
same is to be admitted in regard to Rose Diamonds,
provided their expansion does not exceed the limits
prescribed in the case of spread Brilliants.
And, if it be admitted, as some have asserted, that
there is a superior excellency in Brilliants, what
must be the consequence, but that Rose Diamonds
must sink in their value, to the great prejudice
of the most noble and ancient families, who are
greatly possessed of them as being a more ancient
jewel than Brilliants? But, on the contrary, it will
appear that Rose Diamonds, when truly manufac-
tured, are not inferior to Brilliants, all circumstances
considered.
DIAMONDS AND PEARLS.
19
SOME
Of the Form of a Rose Diamond.
OME observations are now to be made concern-
ing their form. Their being called Rose Diamonds
probably took its rise from their shape, in some
measure, resembling that of a rose-bud before it
expands its leaves. They appear in a kind of semi-
globular form, only terminating in a point at the
top; which form, and likewise the work, or facets
thereof, covering the whole face of the stone, being
more equal, exhibit a more even display of beauty.
than a Brilliant, whose lustre is derived from the
angles or facets of the sides only. And as their
angles are larger than those of a Brilliant, they
throw forth more copious rays, the lustre of which
appears to be equivalent to the sparkling vigour of
the smaller and more numerous angles of a
Brilliant.
The fitness of asserting the dignity of the Rose
Diamond manufacture having been shown, the man-
ner in which it is to be performed is next to be
pointed out. But first, it is necessary to lay down
what is requisite to constitute a complete Rose
Diamond. A round or circular stone is found the
fittest for that purpose, because its form is the most
beautiful, and productive of more vigour than any
other shaped stone, which arises from its admitting
of more equal and better connected facets than
other shaped stones will allow of. And for this
20
A TREATISE ON
further reason, that the same substance and
manner of proportioning which renders them most
complete, will render stones of any other shape
as beautiful as their forms will admit. The right
substance, proportions, and manufacture of a cir-
cular Rose Diamond, are as follow.
Of the Manufacture of a Rose Diamond.
'HE depth of the stone from the base to the point
THE
must be half the breadth of the diameter of the
base of the stone, and the diameter of the crown must
be of the diameter of the base, and the perpendicular
from the base to the crown must be of the depth
of the stone; and then the lozenges, which appear
in all circular Rose Diamonds, will be equally
divided by the ribs that form the crown. The upper
angles, or facets, will terminate in the lower point.
of the stone, and the lower in the base or girdle.
In the 6th Plate, there are four draughts of Rose
Diamonds manufactured by the before-mentioned
rules. The first is a side view of a circular shape;
the second, an horizontal view of the same; the
third, an oval; the fourth, a drop. Their several
parts are explained by the first and second draughts.
As to the first, a, is the point; b, the crown; c, the
girdle. The upper triangles, or facets, show half
the work of the crown; the under triangles, half
DIAMONDS AND PEARLS.
21
the side. As to the second draught, the common
intersection of the six cross lines meeting in the
centre of the draught, is the point; the lines that
form the hexagon, and the triangles within it, com-
pose the crown; the triangles without the hexagon
compose the sides; the outlines show the girdle.
All lines in the draughts are called ribs in Diamonds,
except what express the girdles. These draughts
are representations of Rose Diamonds of 36 carats
weight each, and may be of perpetual use to give a
right idea of their proper figures and workmanship.
Of the Sizes of Rose Diamonds, and their Use
in Discovering Ill-Wrought Ones.
IN
N the following Plates 7, 8, 9, and 10, is exhibited
a list of 55 draughts of circular Rose Diamonds,
from one carat weight to an hundred carats, which
are so many tests to prove the truth or defects of
any manufactured stone of that kind. Their use,
as in the case of Brilliants, will be shown in prov-
ing a Rose Diamond to be either truly made or not.
For example, suppose one of five carats weight; if
it be truly made, it will be as expanded at the base
or girdle as No. 18 of five carats, and the size of
the crown will also agree therewith, its depth will
be likewise half its diameter or breadth. But, if it be
basely made, and left loaded with undue weight,
22
TREATISE ON
A
J
exceed one of
Such a stone, `
its expansion at the base may not
above three or four carats weight.
according to the degree in which it falls short of
its just size, will partake of some, or all the fol-
lowing defects. Either its depth from the base to
the point will exceed the rule; or, though it should
not be too deep, its sides below the crown may be
too upright, which will be discovered by the crown
exceeding its proper extent, and that will conse-
quently cause a flatness from the crown to the
point, or the crown may be situated too high; if so,
the size of the crown may not exceed its just extent,
but then it will occasion an increased flatness of the
crown, and produce an extravagant depth below it,
or the girdle may be left too thick. If any Rose
Diamond is made after this manner, it will, accord-
ing to the degree in which it is thus defective, be
injured in its shape, spirit, and lustre; and, there-
fore is not to be valued by its weight, but only as
it agrees in size with any in the list; for the same
reasons as are given in the like case of Brilliants.
Of the Method of Manufacturing and Valuing
Spread Rose Diamonds.
THE next thing to be regarded is the manner of
making and valuing Spread Rose Diamonds. As
DIAMONDS AND PEARLS.
23
to the manner of making them, what is necessary to
be observed is, that their crowns must be of such an
extent, and placed in such a situation, as to pre-
vent any disproportionate flatness in the crown,
and unequal division of the lozenges; and that
they be made as thin at the girdle as is consistent
with safety in setting them. This is all that is
necessary to be observed on that head. As to
valuing them, the same method is to be observed
as in the case of Spread Brilliants in all respects.*
From what has been said of Rose Diamonds it
seems evident, taking in all circumstances, that
they deserve as much esteem and regard as Bril-
liants, and are entitled weight for weight, to an
equal value; some persons with us, and those of
great reputation for knowledge in Diamonds, pre-
fer the former to the latter; but although this be the
opinion of particular persons, it seems no better
grounded than that of others in giving Brilliants
the preference; for the same consequence must
follow from thence to the possessors of Brilliants as
has been mentioned concerning the possessors of
Rose Diamonds, which was, that if Brilliant Dia-
monds were preferred to Rose Diamonds, these lat-
ter must sink in their value; so, on the contrary, if
* This article of making Spread Rose Diamonds, is as
necessary to the same ends and purposes as the manufacture
of Spread Brilliants, inasmuch as they occupy thinner matter
than Brilliants can.-Note by David Jeffries.
24
A TREATISE ON
Rose Diamonds are preferred, Brilliants must sink
in their value, and if they are equally esteemed and
valued, as appears they ought to be, it will conduce
to the saving of weight that a bias to either mode
of working will unavoidably occasion.
The next thing that falls under consideration is
the method of valuing Diamonds.
The first Method of Valuing Wrought Diamonds
in conjunction with Rough Diamonds, out of
which they are supposed to be wrought.
AN example is here given to show in what man-
ner the value of a manufactured or Wrought Dia-
mond of one carat is to be found, upon the principle
advanced, supposing rough Diamonds to be valued.
at £2 per carat.
The weight of such a stone must be doubled (on
account of half being supposed to be lost in working
it), which is considered as its original weight, mak-
ing two carats; then multiply that weight into
itself, which squares it and makes four; lastly mul-
tiply the four by two, that produces £8, which
is the value of a stone of one carat wrought or
polished, and is equal to the value of the rough
Diamond of two carats, out of which it is supposed
DIAMONDS AND PEARLS.
25
to be made. This single instance is here given to
show the value of rough Diamonds in the price of
wrought ones, and as a further explanation of the
rule of valuing them, and previous to the offering of
any other, it is to be observed that although £2 is
'laid down as the general price of rough Diamonds, †
it is nevertheless to be understood that rough Dia-
monds differ in their value according to their differ-
ent degrees of perfection or imperfection, and
according to the loss of weight they may be sup-
posed to sustain in being truly wrought; as it is
well known that some will lose abundantly more
than others arising from their ill forms, and other
defects that may attend them, which defects are so
numerous and difficult to be expressed, that what
may be said of them would probably not be under-
stood but by the most experienced traders and
manufacturers of them. This consideration, and
that of its being but of little concern to the public,
prevents my saying anything more relating thereto.
In further explaining the principle of valuing
* The mode of calculating the value of stones has, since the
days of Jeffries, undergone considerable modifications, and it
is difficult now to lay down any exact rule of valuation, so
much depending on the colour, size, and form of the crystals.
The price of Diamonds has, within the last quarter of a cen-
tury, greatly increased, notwithstanding the recent discoveries
in South Africa. The values will continue to fluctuate accord-
ing to circumstances, and no arbitrary rule can be given
that shall prove a correct guide for every period.
†The value of Diamonds ranges, for those under two carats
in weight, from £2 15s. to £5 5s. per carat, according to the
nature of the stone.
C
26
A TREATISE ON
:
wrought Diamonds, three other instances, besides
that already given, will be offered, to show the opera-
tion of the principle in coming at the value of
wrought Diamonds, which, it is judged, will be
sufficient in all other cases in this way of proceed-
ing.
After that will be offered three more of the
same weight in a different manner of proceeding,
but to the same end.
Here it may be proper to hint, that all the instances
that will be given, are founded upon the price of
rough Diamonds in general, being put at £2 per
carat, viz, good and bad blended together, as has
been before noticed; so that £2 is the price of the
middle sort only. And it is also to be remembered
that in manufacturing, half the weight is supposed
to be wasted. And as mistakes may be made in
calculating the value of particular Diamonds, in the
manner hereafter prescribed, it is here noted that
the prices of Diamonds, from one of one carat to
one of an hundred carats, of this degree of good-
ness, are contained in Plates 11, 12, 13, 14, 15, 16,
which will prove the truth or falsity of any calcula-
tion, and it is also to be observed, that the expense
of manufacture or workmanship, is excluded in all
the instances that will be given on this occasion, the
reasons of which will hereafter appear.
Now follow the three other instances proposed
to explain this first method of finding the value of
any wrought Diamonds.
DIAMONDS AND PEARLS.
27
The First Instance.
To find the value of one of five carats weight, the
weight must be doubled, on account of half being
supposed lost in working it; that replaces the ori-
ginal weight, which makes ten carats; then multiply
ten by ten, that squares the weight, and makes one
hundred carats; and lastly, the one hundred must
be multiplied by £2, the price of one carat; that
produces £200, and is the value of a wrought stone
of five carats, and the price of the Diamond when
rough.
EXAMPLE.
10 Carats
Multiplied by 10 Pounds.
Makes £100
Multiplied by 2 Pounds.
Makes £200
Second Instance.
To find the value of one of five carats the
weight must be doubled, that makes ten; next
multiply that weight by four, to bring it into fourths
or grains, which makes forty-one; then multiply
forty-one by forty-one, that makes one thousand six
hundred and eighty-one, the square of the weight
28
A TREATISE ON
in sixteenths: therefore divide the one thousand six
hundred and eighty-one by sixteen, that brings it
again into carats, and makes one hundred and five
carats, which multiplied by two pounds, produces
£210 2s. 6d. and is the value of the stone, rough
or wrought.
EXAMPLE.
Carats
10
1
4
4I
4I
41
164
Carats
16) 1681 (105 Te
2
£210 2 6
*A Brilliant pure and perfect, weighing five carats, now
possesses a far greater value. In 1865 the value of such a gem
was £320; two years afterwards, in 1867, the value had increased
to £350, and at the present time would be worth, owing to the
increased demand of late years for Brilliants, from £350 to
£375. It is now extremely difficult to give fixed rules for the
purpose of ascertaining the intrinsic value of Diamonds. But
the fact must not be overlooked that David Jeffries is here.
speaking of what may be termed second rate or middle class
stones.
DIAMONDS AND PEARLS.
29
Third Instance.
To find the value of one of five carats, the
weight doubled is ten carats; reduce that weight
into grains, by multiplying it by four, that makes
forty-two; then multiplying forty-two by forty-two,
that makes one thousand seven hundred and sixty-
four, the square of the weight in sixteenths; which
divide by 16, that brings them again into carats,
and makes one hundred and ten carats and 1,
which multiply by 2l., that produces 220l. 10s. and
is the value of the stone, rough or wrought.
EXAMPLE.
101 Carats
4
42
42
84
168
Carats
16) 1764 (110 1
2
£220 10
30
A TREATISE ON
The Second Method of Valuing Wrought Diamonds
in Conjunction with the Rough Diamond, out
of which they are supposed to be wrought.
то
First Instance.
find the value of a Diamond of five carats
weight, as in the foregoing cases, so in this the
weight must be doubled, that makes ten carats. As
a rough Diamond of one carat is valued at two
pounds, every carat in this stone accumulates ten
times that value, and so every carat in this stone
is to be valued at twenty pounds, that will produce
two hundred pounds, and is the value of the stone,
rough or wrought.
EXAMPLE.
10 Carats
Multiplied by
20
Makes the total 200 Pounds
Second Instance.
89
To find the value of one of five carats the
weight doubled makes ten carats ; next reckon
that weight in the foregoing manner, that makes.
every carat in this stone worth twenty pounds ten
shillings; so just multiply ten carats by twenty
DIAMONDS AND PEARLS.
31
pounds, that makes two hundred pounds, then mul-
tiply ten carats by ten shillings, that makes one
hundred shillings or five pounds; next add the value
of a fourth of a carat at the rate of 20l. 10s., that
makes 51. 2s. 6d. Lastly, cast up these three sums,
the total will be 210l. 2s. 6d., and is the value of
the stone, rough or wrought.
Multiplied by
Makes
EXAMPLE.
10 Carats
20 Pounds
£200
10 cts. multiplied by 10s. makes 5
The value of of a carat at
2ol. 10s. is
Makes the total
}
526
£210 2 6
Third Instance.
To find the value of one of five carats 4, the
weight doubled makes ten carats ; reckon that
weight as in the two other cases, that makes every
carat in this stone worth twenty-one pounds: so
multiply ten carats by twenty-one pounds, that
makes 210l., then add the value of the half carat at
21l. per carat, that makes 10l. 105. Lastly, add the
two sums together, the total will be 220l. 105.,
is the value of the stone, rough or wrought.
and
32
A TREATISE ON
Multiplied by
Makes
EXAMPLE.
10 Carats
21 Pounds
£210
The value of the carat
added, which is
Makes the total
}
ΙΟ ΙΟ
£220 10
The instances that have been given of two me-
thods for finding the value of wrought Diamonds,
as they stand connected with the rough (out of which
they are supposed to be made), it is apprehended
are a sufficient explanation of the principle for valu-
ing rough and wrought Diamonds, and prove its
being founded on reason.
of the Method of Valuing Wrought Diamonds,
exclusive of any regard to Rough Diamonds.
A F
S instances have been given of two different me-
thods of attaining the value of wrought Dia-
monds, in which cases the value of rough Diamonds
of double their weight have been jointly considered,
they being supposed to be made from such rough
Diamonds; three instances of manufactured Dia-
monds of the same weights will now be offered, to
1
DIAMONDS AND PEARLS.
33
show in what manner their value may be found, ex-
clusive of any regard to rough Diamonds; and as
the last method appears the shortest and most easy
to be understood, that method will be made use of
on this occasion.
This is to be known by applying the price they
bear manufactured, which has been shown, viz.,
that as rough Diamonds are valued at two pounds
per carat, a wrought Diamond of one carat is worth
eight pounds; so to find the value of a stone of that
degree of goodness, whatever number of carats are
contained in such a Diamond, each is to be valued
at eight pounds, and whatever sum they make must
be multiplied by the weight of the Diamond. The
instances are as follows:
First Instance.
To find the value of such a Diamond of five carats
weight, reckon every carat at eight pounds; then
multiply five carats by eight pounds, that makes
forty pounds, so every carat is to be valued at forty
pounds; then multiply five by forty, that produces
2007., and is the value of such a Diamond.
EXAMPLE.
5
Carats
Multiplied by
40
Pounds
Makes the total
£200
C2
3-4
A TREATISE ON
Second Instance.
To find the value of one of five carats, at the
rate of eight pounds per carat, multiply five by eight,
that makes forty, then add to that the value of of
eight pounds, that is one pound; so the value of
every carat in this stone is forty-one pounds, then
multiply five by forty-one, that makes 205l., next
add the value of of forty-one pounds, that makes.
51. 2s. 6d. These two sums cast up produce 210l.
2s. 6d., and is the value of the Diamond.
8
EXAMPLE.
5
Multiplied by
Carats
41 Pounds
Makes
£205
To which is to be added the
value of of 411. which is f
8
Makes the total
5 26
£210 2 6
Third Instance.
One of five carats, the value of each carat is
forty-two pounds; multiply five by forty-two, that
makes 210l., then add the value of of forty-two,
which is rol. 10s., makes the total 220l. 10s.
DIAMONDS AND PEARLS.
35
Of the highest and lowest Price of Rough and
Polished Diamonds.
HAVING explained the different methods of find-
ing the value of rough and wrought Diamonds
of the middle sort, the first being rated at two
pounds per carat, the second at eight pounds. As
rough and polished Diamonds may be of a higher
or lower value, it remains to show what may be the
highest and lowest of each.
First-I shall speak of rough Diamonds, and
shall suppose three prices: for instance one pound,
two pounds and three pounds; the middle being two
pounds, there appears an advance of one pound
above the middle price, and a fall of one pound be-
low, which is a deviation of fifty per cent each way,
and makes the worst sort be but one-third the value
of the finest.
That the two extreme prices naturally proceed
from that of the middle price, I shall endeavour to
prove, and in order thereto, I shall first show, that
no rough Diamond which is not worth one pound
per carat, ought to be manufactured; because all
that are of less value must be very defective, carry-
ing many or all of the following blemishes: fouls
or stains, specks, flaws, being veiny, craggy, ill-
formed, and of an ill-colour; which, consequently,
must obstruct and defect the purposes of manufac-
ture; for with all art can do, they will be void of
36
A TREATISE ON
lustre, which will sink them below the rank of a
jewel.
Next, it is to be observed, that all under that value
will sell for as much, to be used in cutting or form-
ing the better sort, as any one can afford to give for
them, with the view of manufacturing them, for the
expense of workmanship must be the same as for
better stones if well done, and if not well done, it
will add to the other defects, and the loss of weight
must be greater than what attends better stones, by
its being frequently necessary to discharge or lessen
the defects before-mentioned; indeed, when a stone
of a very large size falls in the way, it may be
thought worth the expense of working, as its size
may recommend it. These being rarely to be met
with, but not as ornamental to anything, such may
be valued below 41. per carat, as the buyer and seller
may agree on.
As it cannot but appear that no rough Diamond
ought to be wrought, that is not worth one pound
per carat, this must be allowed the lowest price of
rough Diamonds worthy of manufacture; which, as
we have already observed, is half the value of the
middle price; so allowing as much advance above
it, makes the price of the finest rough Diamonds
worth 37. per carat.
This being admitted, it shows that manufactured
Diamonds of the worst sort are worth 41. per carat,
and the finest 12l. per carat; and this, probably,
DIAMONDS AND PEARLS.
37
will be thought scope sufficient to employ specula-
tion and judgment; and if the value of rough Dia-
monds should rise or fall, the middling price must
be always that which the whole was valued at, good
and bad blended together; and as many prices as
will lie between those of the lowest price and those
of the middle price, so many must be admitted above,
the middle price, and that will determine the highest
price, or, in other words, whatever the worst are
valued at below those of the middle sort, so much
must the finest be valued at above the middle sort.
And, therefore, the value of all Diamonds is to be
adjusted within the limits of the extreme prices.*
* There is a great difficulty in properly adjusting, with any
degree of accuracy, a scale of charges for Brilliants which would
be in every instance applicable. It may here be remarked that
the value of stones of the first quality of a less weight than two
grains, average at the present time from £10 10s. to £II IIS.
per carat; the second quality £9 9s. per carat; and the third
from £7 to £7 10s. per carat. A Brilliant weighing one carat
will now realise from £20 to £30; two carats £75 to £85; two
carats and a half, £90 to £120; three carats, £135 to £145;
three carats and a half, £165 to £180; four carats, £215 to
£225; five carats from £345 to £360. These prices are estimated
for Diamonds of the first quality. It is impossible to fix the
value of stones above five carats, as the purchase of large stones
is always the subject of an arrangement altogether independent
of market rates, and will greatly depend on the demand as well
as the supply in the market.
38'
A TREATISE ON
Remarks on Brazil Diamonds.
FROM the want of this knowledge, and the rule
of valuing Diamonds, has arisen the wide dif-
ference of Jewellers' sentiments, concerning their
just and natural value; the ill-effects of which dif-
ference to individuals I shall be silent about, that
having been too sensibly felt to need any remarks,
but proceed to show what an effect it has had in
times past, on this important property in general.
In the year 1733, rough Diamonds were not worth
twenty shillings per carat; in the year 1735, not
worth thirty shillings; in the year 1742, not worth
more than thirty shillings per carat; all which may
clearly be made to appear, from public sales in the
before-mentioned years. Catalogues of them I have
preserved, on which I have made particular remarks
and shall be ready to show them on any proper
occasion. I have been the more careful to preserve
them, believing there never will be the like exhibited
again; and the farther cause of publishing these
facts, is to show that if the traders had better known
how to value Diamonds at that time, and had been
better informed of the real cause of so great a plenty
as then appeared, they would not have discovered
so great a consternation as then possessed them,
which occasioned many even of the most capital
traders in London, to believe that Diamonds were
likely to become as plentiful as transparent pebbles,
?
DIAMONDS AND PEARLS.
39
and they were so far influenced by this opinion that
most of them refused to buy Diamonds on any
terms.
The adventurers were chiefly persons of low cir-
cumstances, on which account the Lisbon merchants
dreaded any returns made them in Diamonds or any
sent them for sale; being forced to deal with such
persons upon credit, and at any price that these
purchasers were pleased to give for them.
One of the most considerable Portugal merchants,
with whom I dealt, told me, in the month of January,
1733-4, at which time I bought a parcel, to the
amount of seven hundred and fifty pounds, that he
had been forced (for want of more reputable buyers)
to sell and give credit for many hundreds of pounds,
to such as he would not have trusted with five
pounds in cash, and that he found other merchants
were in the like case; on which account there were
many large parcels returned to Lisbon, they not
being able to find buyers enough, even of this sort,
to take off their goods.
I shall here mention some other matters that
arose in conversation at this time. This gentleman
observing me to be more exact than others, in
weighing the large stones of the parcels I bought
of him, and some of other parcels, asked me the
reason of it, upon which I told him that no man
who did not know how to value Diamonds in pro-
portion to their weight (whatever knowledge else
40
A TREATISE ON
he might have of rough Diamonds), could be a pro-
per judge of the value of any stone. Upon which he
was pleased to say, if I had that secret, he appre-
hended I might get what money I pleased. I told
him it could be of no service to me till it became
public, and the world made sensible of the truth of
the principle. Upon this he said, he thought it
might be of great use to make it public, and asked
if I did not intend to communicate it to the world.
I told him it was my intention, when circumstances
rendered it more proper; observing it would be by
no means proper then, as the public, and likewise
the traders in them, were so apprehensive of the
Brazil mines producing an inexhaustible store;
judging from thence, the world would scarcely think
Diamonds worth any consideration, especially as
Jewellers so undervalued them.
As this has been, and still is, in a less degree,
the state of the case in regard to Diamonds, it may
be proper to enquire, whether it be fact, that these
mines have produced any Diamonds or whether the
Diamonds that have been sent from thence, be not
such as are procured by trade. Having many years
past been very solicitous to know the truth of this
matter, I have spared no pains to come at as good
a knowledge thereof as I could procure, and what
information I have met with I shall disclose.
In the year 1734, I had the pleasure of being ac-
quainted with a gentleman that had been, but a few
DIAMONDS AND PEARLS.
4I
years before that time, governor of Fort St. George.
He told me, upon my talking with him about the
Brazil mines, that he did not believe a tittle of the
report, and gave this as a reason for his disbelief
of it, namely:-that when he was at Fort St. George,
he was informed that the Brazil people had long
carried on a secret trade with the Indian people at
Goa, for Diamonds, and was assured they had a
vast stock, but not very fine, they generally choos-
ing to buy the more indifferent sort, for the sake of
cheapness; and he said, whatever quantity came
from thence, would not alter his opinion in regard
to the value of what he was possessed of, nor would
he abate of the price they were valued to him at in
India, saying they only knew how to value Dia-
monds. In this resolution he persisted to his death,
which happened but a few years since. Some of
these Diamonds he sold before his death at his own
price, and he then said it was his opinion, that their
sending their Diamonds to Lisbon was not a matter
of choice, but necessity; being forced thereto, in
order to raise a large sum of money to discharge
great arrears of indulto, which they then owed the
King of Portugal; and the same has, since that,
been said by others. And, moreover, it has been
said, that the late King having been made acquainted
that they were greatly in debt to their European
correspondents, he insisted upon their sending a
sufficient quantity to discharge those debts; and
42
A TREATISE ON
when they came to Lisbon, in order to give im-
mediate satisfaction to the merchants, it was said
the King ordered them to be sold in a public
manner for the sake of expedition; and some have
thought it was done out of resentment to his Brazil
subjects, for their using him and the European
merchants ill, he knowing they had it in their power,
long before, to have remitted these Diamonds.
Another circumstance had liked to have escaped
my notice which is, that it has been also reported
here by persons of figure and unquestionable vera-
city, who happened to be at Fort St. George when
it was reported that the Brazil mines had furnished
Europe with a great quantity of Diamonds very
cheap, that the Indian people laughed, and said it
would not alter their price.
From what has been observed, there seems room
to think, that these Diamonds are the effect of the
King of Portugal's subjects' trade, and not the pro-
duce of his Brazil mines; for it cannot be thought
any prince would have countenanced such a disad-
vantageous method of disposing of the produce of
his own mines, as was practised in getting rid of
them, notwithstanding any redundancy; on the con-
trary, that he would have restrained the sending any
quantity that must tend to sink their value, which
is always carefully avoided by the Indian people.*
* Up to the end of the 17th Century, Diamonds were wholly
derived from India, from the mines of Sumbulpoor and Gol-
DIAMONDS AND PEARLS.
43
And if it were true that his Brazil mines so
abounded with Diamonds, they must be come at
with a great deal less expense than attends the
search for Diamonds in India, and of course he
must become the richest prince in Europe, for it
would be an additional employment for his Brazilian
subjects, in consequence of which his commerce
must be greatly increased; inasmuch as we should
always encourage it, rather than that of the Indian
trade, on account of our purchasing Diamonds in
India chiefly for bullion. And can it be supposed
a wise prince would disregard a gift of Providence
so highly esteemed by the eastern part of the world?
And, therefore, the methods made use of must be
supposed to proceed from the late King's knowing
they were the effects of the trade; if so, it cannot
but be judged a wise and just step in him, to force
them to discharge their obligations to himself and
their correspondents, knowing they could procure
no advantage to them by lying in their hands as a
dead stock. Besides, trading in Diamonds has been
disallowed by the late King, and to conceal it from
his knowledge is supposed to be the reason of their
conda; the mine of Sierra do Trio, in Brazil, was discovered
in 1727; and some were found in the Ural Mountains, in the
year 1829. The latest discoveries are those of South Africa,
and the Diamond diggers of the Vaal have in most instances
been well rewarded for their exertions. Of course, in such a
speculative employment, there must, of necessity. be many
whose labours have been almost if not entirely unproductive.
44
A TREATISE ON
giving out, that the Diamonds they were formerly
possessed of were the produce of his Brazil mines;
and to make it the more plausible they suffered it to
be reported that they were of a different nature, as
well as worse than India Diamonds.
Upon this occasion I will venture to say (from
critical observations in an extensive commerce and
manufacture of both), that there has not appeared
to me a circumstance, in those called Brazil Dia-
monds that I have not found in India Diamonds;
and it is likewise noticed, that some year's cargo
from the Brazils have been as fine as any year's
cargo from India, and that the small Diamonds
have sold at as high a price as ever was given for
small India Diamonds. And it is also remarked,
that what have of late been brought from Brazil, we
hear but little of more than their quantity yearly
lessens, notwithstanding their price is raised more
than treble of what they bore some years ago.
There are various sentiments among traders con-
cerning the cause of it, but being much divided in
their opinions, I shall not trouble my readers there-
with, not doubting but their sending so few, will
appear to arise from their not being possessed of
more. And, from hence may be inferred, that they
are interrupted in this commerce, and deprived of
the means of procuring them as formerly; which
means are supposed to have been their purchasing
them with Brazil gold, wherein the Brazil mines
DIAMONDS AND PEARLS.
45
are known to abound in a profuse degree; and in
this sense it may be said, the Diamonds we have
had from thence are the produce of the Brazil mines;
and if there be a check or an interruption thrown in
the way of this barter, we cannot expect to have
such quantities as formerly, although more or less
may always come from thence, which has been the
case before the great glut appeared; but they were
not then called Brazil Diamonds, and what was
brought from thence was conducted with great
secrecy, and it is likely this trade will be continued,
from the circumstance of Diamonds being so port-
able a commodity, and what may be conveyed
with great secrecy, however strict his Portuguese
Majesty's orders may be in prohibiting thereof. As
to the political reasons for prohibiting this traffic,
it is not my province to meddle with that.
Amidst what has been said to show the impro-
bability of the Brazil mines having produced the
Diamonds that of late years have been placed to
their account, the circumstance that has been be-
fore-mentioned deserves more than ordinary notice,
therefore I shall recite it again; which is, that not-
withstanding the India people knew what despicable
prices Brazil Diamonds sold for in Europe, in the
before-mentioned years, they kept up the price of
their Diamonds, which seems to prove they were
the sellers of those Diamonds to the Brazilians, and
serves to explain what they meant by laughing at
46
A TREATISE ON
the report of the Brazil mines furnishing Europe
with Diamonds, and their saying it would not alter
their price.
This conduct, surely, deserves the highest ap-
plause, for had they copied after the Brazilians, this
great article of wealth, by this time, would have
been reduced almost to nothing; the ill effects of
which words cannot sufficiently express: the pre-
vention of this evil the Indian people must have the
honor of.
To maintain as invariable a price of these jewels
as is possible, must be of the greatest utility to the
public, which they appear to be sensible of from
their past conduct; but there is more to be offered
in proof of this.
It is attested by unquestionable authority, that
when they find a slack demand for Diamonds, they
always withdraw them; the consideration of any
quantity they may be possessed of seems to be no
motive with them for abating their price; which is
believed to arise from their supposing they have
competitors to subject them thereto; and from what
has been observed, the truth of it can scarcely be
doubted, and their manner of trading with us seems
to be a further proof it, which is thus:-
They first find out what sorts are wanted, and
then show such goods and put their price; if they
are sold they have their demand, for they suppose
themselves to be the only judges of their value, and
}
DIAMONDS AND PEARLS.
47
it does not appear that anyone has disputed the
truth of it. From hence it is, that Diamonds are
sent here in bulces, which means parcels of Dia-
monds neatly tied up in muslins, and sealed by the
sellers of them; which Diamonds are generally
bought here by the invoice, that is, are bought be-
fore they are opened; it being always supposed they
contain their value which they were sold for in
India, and the buyer here gives the merchant such
a profit as contents him. The Diamonds being
thus bought, the buyer opens the parcel, separates
them, and then values them separately as his judg
ment directs; making to himself, likewise, such a
profit upon the whole parcel as he thinks proper.
And as this is the case, it is referred to the con-
sideration of reflecting minds, whether or no any
man can properly judge of the value of stones of
different sizes and properties, without some rule to
direct his judgment. As for the different properties
of Diamonds, speculation assisted by the knowledge
acquired in manufacturing Diamonds, is the only
guide; but whether any can judge of their value,
regarding their magnitude, is the thing in question.
It seems as if our traders thought the Indian people
were masters of some rule for that purpose, by placing
such confidence in them as it appears they do by
this representation; and it is believed, when the people
of the European part of the world are acquainted
with the true method of estimating Diamonds, it
.
78
A TREATISE ON
will be found that the people of India have generally
valued their large Diamonds alike at all times, let
the demand for them vary as it may.
If that be the case, is not this issuing out another
staple commodity, like that of gold and silver? And
although its value is not ascertainable to so great
an exactness as either of those by an assay, yet it
may appear they are reducible to as great a near-
ness in speculation as either of the other two. But
however beneficial this may be, the value of Dia-
monds can never be at all settled in Europe, whilst
we are amused with the notion of the Brazil mines
being productive of Diamonds. How far it is the
interest of these parts of the world to be well in-
formed of the truth of this matter, is left to the con-
sideration of the public.
But suppose it should be remarked, that although
Diamonds in India, may at all times be near the
same value, it cannot be the case in other parts of
the world, arising from various circumstances: the
chief cause of which variableness in the price of
Diamonds or other Jewels, in other parts of the
world, cannot but be seen to be the disagreement
in the sentiments of Jewellers concerning the natu-
ral value of them. But the extraordinary instances
in the late wars in Germany, will be a farther proof
of it, inasmuch as it has been told us by public
papers, that not above one-third or one-fourth of the
money which gems have cost, could be procured by
DIAMONDS AND PEARLS.
49
intrinsic worth
Must not this
way of pledge or sale; indeed, the avarice of the
buyers may have some share in occasioning so
great a loss. Does this prove the
of jewels, so frequently talked of?
be a vast discouragement to great personages from
vesting themselves with this property? How fit,
therefore, is it to render them as invariable in their
price as the nature of things will admit of, since they
possessed themselves thereof, not only for personal
ornaments, but also as articles of solid treasure, to
serve such emergencies as have been noticed? And
it is known, that there are some rough Diamonds
of great price, as well as polished in Europe, which
have been bought upon that principle.
Since it is thus, nothing can be a greater induce-
ment to persons of high stations to purchase Dia-
monds, than rendering their value more staple.
And as nothing can accomplish that so much as
being well acquainted with their true value, the fol-
lowing method will be found the only way of coming
at that knowledge.
It appears from the reason of things, that all large
Diamonds are to be valued according to the rule
advanced, by the price that one of a carat bears,
which is similar to a stone whose value you would
know, for as you value the weight in a stone of one
carat, so must you that of a stone of the same pro-
perties, let the weight be what it may.
And as a
* David Jeffries applied the same rule to stones varying from
D
50
A TREATISE ON
farther proof of its being right, it will be found that
Jewellers of the greatest experience and knowledge,
have generally estimated Diamonds as this rule
directs, by dint of sound judgment, and as the
younger and less experienced must want some
assistance in this important concern, this will put
them in the right way, and by means hereof the
value of Diamonds will be made universally known,
as it is in so narrow a compass as that of anyone's
making himself acquainted with the worth of a
Diamond of a carat weight, which, it is presumed,
persons of good judgment cannot be at a loss to
know, let them be good, bad or indifferent, and that
such will agree in their sentiments concerning the
value of a stone of a carat weight, be it, as it may,
from five to ten per cent.
one carat upwards. The fallacy of this mode of calculating
the exact value of Diamonds in the present day, arises from
the fact, that for the large descriptions of gems frequently the
most exorbitant prices are obtained, more particularly if it be
what is termed a fancy stone. If a Diamond possesses a very
decided colour, such as red, blue or green, it is called a "fancy
stone." Instances have been known of a stone of five grains
of a brilliant emerald green, realising no less a sum than three
hundred guineas, for which, had it been white, not more than
£28 or £30 could be obtained; hence the difficulty of laying
down a fixed scale according to weight.
DIAMONDS AND PEARLS.
51
THE
Of the Table of Prices of Diamonds.
HE next thing to be taken notice of is a table,
which will be found in the 11th, 12th, 13th,
14th, 15th and 16th Plates. This table consists of
the prices of Diamonds, from one carat weight to
one hundred carats, formed upon the principle of
valuing them by the square of their weight, upon
the supposition that the governing price of rough
Diamonds, good and bad blended together, is £2
per carat; so that £2 is to be reckoned the mean
or middle price, and will be found of great use to
prevent the trouble of calculating the price of every
stone by the rule. If any stone differs in its value
from this mean or middle price, whether higher or
lower, so much per cent. is to be added or deducted,
as judgment shall direct. It may be observed, that
the tables do not descend to sixteenths of a carat;
it is omitted for brevity's sake, which may be sup-
plied by casting up any two adjoining prices, and
then take the half, that will give the prices of the
intermediate weight. For example: a stone of one
carat will be seen to be the first article in the table,
and to come to £8. To find it out by this rule, the
*The present value of Diamonds of the first water, not
exceeding two grains in weight, is £10 to £10 10s. per carat ;
the second quality, £8 5s. to £8 10s. per carat; the third,
£7 IOS. Coloured Brilliants under one carat, range from £4
to £7 per carat, according to their shade, and to correctly esti-
mate the value of these stones, must depend, in a great
52
A TREATISE ON
A
method is to multiply 2 by 2, that makes 4, which
is the square of its weight; then multiply 4 by £2,
the price of one carat, that makes £8. Here it is
to be remembered, that all the prices which the
tables contain are supposed to be of the middle
sort, and also that half the weight is supposed lost
in making, which occasions the first multiplying by
2; but as this method is more laborious and intri-
cate in regard to stones of odd weights, the tables
will be found of much convenience.
8
An instance is here given as a proof of a Diamond
of seven carats, in the two different methods of
valuing. For example: the first method is this
the weight of a stone of seven carats must be
doubled, which makes fifteen carats; next, that
weight must be multiplied by 4, to bring it to grains,
that makes 63; then multiply 63 by 63, that makes
3969, the square of the weight in sixteenths; there-
measure, upon the judgment of the purchaser. To give any
closer valuation than the figures above-mentioned, would be
useless, and as fluctuations are constantly occurring in the
values of gems of all kinds, it will at all times be necessary to
watch the changes that take place in the market.
* The weights by which Diamonds and Precious Stones are
calculated are as follows:-4 grains I carat; 151 carats 1 oz.
troy. No fixed rule can be laid down by which the value of
Diamonds can be calculated according to any arbitrary con-
nection with the weight. For instance, the value of a perfect
one-carat stone, at the present time, is from £18 to £18 18s. ;
and a five-carat stone varies from £310 to £350. According
to the demand and the supply, so will the prices vary.
DIAMONDS AND PEARLS.
53
fore divide the 3969 by 16, that brings it again to
carats, which makes 248 carats and, which mul-
tiplied by £2 produces £496 2s. 6d. The second
method is this: first see what a Diamond of seven
carats is worth per carat, which will be found to
come to £63. First multiply 7 by 63, that makes
£441, then add the value of of £63, which comes
to £55 2s. 6d., these two sums added together pro-
duce £496 2s. 6d., so both totals are alike, and agree
with the price of one of the above weight in the
tables.
$
It will here be proper to observe farther, that no
notice is taken of the additional price which the ex-
pense of manufacture would occasion in each stone.
This is omitted on account of the different prices
their different sizes and weights demand; and like-
wise, on account of the different prices which their
various substances require. These circumstances
render it impracticable to be inserted; and therefore,
the prices of both are contained in four tables, ex-
hibited at the end of the treatise. The first table
contains the price of full-substanced or full-propor-
tioned Brilliants, explained as follows:--the first
column exhibits a supposed increase of size and
weight, from a stone of a carat to one of an hundred
carats. The first five articles are carried on by the
increase of one carat each, the following by five
carats each. The second column contains the price
of their workmanship, according to their increase
54
A TREATISE ON
in weight, at the rate of £1 per carat. The reason
of carrying on the gradation by the increase of five
carats is for the sake of brevity, as the different
prices of the intermediate weights are inconsider-
able, compared with the increased value of such
stones. The first table being explained it will serve
as an explanation of the other three.
The second table exhibits the price of making
spread Brilliants, which is rated at £1 5s. per carat,
and is so done for the following reasons: namely, ·
that all spread stones require more care than full-
substanced ones, and are not so soon despatched.
The third and fourth tables regard the price of
manufacturing rose Diamonds, which manufacture
demanding less labour than that of Brilliants, causes
the price to be one-fourth less, as will be seen by
the third table regarding full-substanced or full-pro-
portioned rose Diamonds. The fourth table regards
spread rose Diamonds, the price of which is the
same with that of full-substanced Brilliants, which
is so raised for the same reasons as have been given
in the case of spread Brilliants.
N.B. The prices in these tables are to be doubled
in wrought stones, half the weight being lost in
manufacturing.
If I had not inserted the different expenses of
manufacturing Diamonds, it would be found want-
ing in the value of every stone, but may now be
easily supplied from the tables just explained. An
*
DIAMONDS AND PEARLS.
55
7
83
instance will fully evince their use, which I will
give in the case of a full-proportioned Brilliant.
For example: suppose the value is required of one
of the mean or middle sort of 7 carats; the Dia-
mond, exclusive of the expense of workmanship,
comes to £496 2s. 6d., the expense of workmanship
must be reckoned at £3 15s. per carat, which comes
to £26 14s. 4 d., that being added the whole makes
£522 16s. 10d.
From the various helps contained in this book, it
may be reasonably expected that such as are skilful
in Diamonds, and acquainted with the current price
of them, will hereafter universally agree.
The innate perfections and imperfections of Dia-
monds come next under notice,
Of the innate Perfections, Imperfections and
Water of Diamonds.
THE circumstances which distinguish the finest
Diamonds are these. Their complexion must
*be like that of a drop of the clearest rock water, and
* Stones exceeding five carats in weight cannot be valued
by any fixed rule. Their value must be determined by their
size, purity, and proportion. It must be borne in mind that a
badly-proportioned stone is always inferior to one that is
properly proportioned.
56
A TREATISE ON
if such stones be of a regular form and be truly
made and free from stains, fouls, spots, specks,
flaws and cross-veins, they will carry the highest
lustre of any whatever, and will be esteemed the
most perfect.
If any are tinctured yellow, blue, green or red, in
a high degree, which seldom happens, they are next
in esteem; but if any partake of these colours only
in a low degree, it sinks their value below the be-
fore-mentioned.
There are other complexions of a more compound
sort, such as brown, and those of a dark hue. The
first of these sometimes resemble the brownest
sugar-candy, the latter dusky iror. And if any
Diamonds are attended with stains, fouls, spots,
specks, flaws and cross-veins, it will abate their
lustre and sink their value. Here it may be ob-
served, that what is commonly called the first water
in Diamonds, means the greatest purity and per-
fection of their complexion, which, as was said, must
be like a drop of the clearest rock water. When
any speak of a Diamond falling short, more or less,
of that perfection, it is expressed by saying it is of
the second or third water, &c., till a stone may pro❤*
perly be called a coloured one. And to speak of a
Diamond imperfectly coloured, and containing any.
other defects, as a stone of a bad water only, is very
improper, as it does not convey an idea of the par-
ticular colour or defects belonging to it.
DIAMONDS AND PEARLS.
57
Of the Superior Worth of Diamonds over
all other Jewels.
DIAMONDS have in every age been esteemed
the chief of Jewels, on account of their innate
specific qualities, which if not exhibited by proper
skill, remain imprisoned. It is certain that in their
natural state they have not so much beauty or
lustre as some other sorts of Jewels, but when truly
and judiciously manufactured, they throw forth a
splendour and lustre surpassing all others, which
justly entitles them to the most perfect workman-
ship, and will consequently be the most likely
means of perpetuating them in the esteem of the
world. And this will tend to establish their worth,
and secure everyone's property therein; whereas a
neglect of exhibiting and displaying their beauty by
proper workmanship, will render them unworthy
ornaments of the great and distinguished, which of
course, must sink their value. These considera-
tions, doubtless, will influence the curious and dis-
cerning to give all due countenance to their being
exhibited, in future times, with that beauty and
lustre of which they are susceptible.
And if the following additional circumstances be
taken notice of they will farther show that Diamonds
deserve the chief regard of all Jewels. First they
are the best repository of wealth, inasmuch as they
will lie in the smallest space of any, and are thereby
D2
58
A TREATISE ON
the most portable and best conveyance of treasure.
Next their superlative hardness secures them from
all injury by wear, as nothing can make any im-
pression on them, or prejudice their lustre, but their
rubbing against each other. They can only be
affected by fire, and that must be strong and lasting
to do them much harm, and the injury they receive
thereby arises chiefly from taking them too hastily
from thence, whereby the immediate impression of
the cold air may possibly produce flaws, &c. A
moderate fire will only occasion a roughness on
their surface, which may be repaired by new polish-
ing.
Reasons for Working Diamonds in a Complete
Manner, and the Consequences resulting from
a Contrary Practice.
WHAT has been said of the superlative properties
WHAT
of Diamonds, &c., seems sufficient to recom-
mend them to the protection of mankind from any
abuse arising by ill-workmanship, as their pleasure,
honour and interest are concerned in it, and nothing
appears wanting to influence thereto, but that of
the world being convinced of the necessity of it,
from being made acquainted with the abuse that
Diamonds have sustained by the contrary practice.
1
DIAMONDS AND PEARLS.
59
To that end I shall first resume the observation that
has been made on small Brilliants, which is, that
they are in general so ill-wrought as to be void of
their true beauty and lustre, and will not fill up by
one-fourth or one-third the space that well-wrought
stones do in a piece of jewelling work; of course
purchasers of such are deprived of one-fourth or
one-third of the show or appearance that well-
wrought stones would make, and of the beauty and
lustre that always accompany such. Next that the
same effects attend stones of larger sizes, made
after the same manner.
N.B. The same ill effects also attend small or
larger rose Diamonds, made in the same manner.
The ends and purposes that are to be served by
this manner of working, naturally fall under consi-
deration: the most that can be pretended is that by
the world being brought into a favourable notion of
these goods on account of buying them at a lower
price by weight than well-wrought stones, trade has
been increased, and more hands employed; but it
cannot mean the increase of England's trade, for
that has been declining many years, and its hands
unemployed, to the great impoverishment of the
whole body of workmen, and those known to be as
good as any, if not the best in the world: and which
has arisen from their refusing to work after this
rude manner, and not being able to support them-
selves by the wages that are given abroad for such
бо
A TREATISE ON
work, which appears not equivalent to the wages
here given to the meanest handicraftsmen.
Admitting our neighbours have increased the
traffic, and employed more hands of the lowest sorts
than we could ever boast of, let the consequences
which are like to flow from this manner of working
be considered.
By the continuance thereof the disesteem that
has of late been shown to Diamonds may increase;
which principally has taken its rise from thence,
particularly in England, and that probably has been
forwarded by the good appearance which crystal
or false stone work, commonly so called, has måde
of late (on which all the embellishment that care
and skill can procure, has been bestowed). This
is observed to the credit and reputation of these
traders and their workmen, and in consequence
thereof this commodity frequently passes for Dia-
monds; and if the same care should be taken in
completing that sort of work for foreign use, they
also may enter into the like contempt for Diamonds;
if so, what will become of this boasted increase of
trade? But if the truth of the Diamond manufac-
ture be supported, their lustre will conspicuously
excel the faint and languid efforts of all crystalline.
matter, with all the helps of art.
To disgrace this first-rate gem by ill-workmanship,
in bringing it down almost to the level of this com-
modity, seems to be very unwarrantable, especially
DIAMONDS AND PEARLS.
61
as it tends to sink this part of public wealth,
and is a manifest discouragement to art and in-
genuity, and also of great prejudice to fair traders,
who scorn to submit to the encouragement of such
mean, deceitful artifices to enrich themselves.
But notwithstanding what has been offered, to
show the impropriety and ill-consequences of work-
ing Diamonds in an ill-manner, it is to be feared
that such as have hitherto found their account in it
will pursue the same method so long as they can
find it their interest so to do. To prevent this
abuse, the sizes of Brilliants and rose Diamonds
are exhibited, by which anyone may know whether a
Diamond of either manufacture be well or ill-made;
and this is thought the most effectual means of
putting a stop to it, judging all persons who have
any considerable value of this kind will afford their
assistance in discountenancing such an injurious
practice; if so, the world will see persons of rank
and fortune distinguished from others, by the in-
imitable lustre of these jewels; for which purpose,
doubtless, they were intended.
But it may be said that many persons of rank and
fortune are possessed of such ill-wrought stones,
and the encouraging of this refinement of manufac-
ture will make them appear in a worse light. This
is allowed; but at the same time, it is to be under-
stood that all ill-wrought stones are capable of being
made as perfect in respect to workmanship, as any,
62
A TREATISE ON
without the least loss of their expansion or breadth,
and that such rectified stones will appear to sight
rather larger than in their present form; for by be-
ing made more open, every part of their upper sur-
face will be more clearly seen, and what loss of
weight they sustain will be compensated by the re-
maining weight being of more value; or, in other
words, that weight will be worth more per carat,
and then such will weigh as much as they ought
when sold, and by this means indifferent Diamonds
may be made fine, if the matter or stuff be such,
which is frequently the case; and the reason of
their being but indifferent before, was their being
overloaded with weight, and otherways ill-wrought,
which obscured their true lustre. This compliance
with what is proposed, will make them of rather
more value than when bought, and the loss to the
purchaser is that which is paid for rectifying them.
This will prove a greater disadvantage to the pur-
chasers of small Diamonds than to the purchasers
of larger stones, as the workmanship of small stones
is a considerable part of their value.
Here it may be proper to observe, that the worst
workmanship is frequently performed on coloured
stones to render them cheap, by which means they
are generally disposed; instead of that, they should
have all the advantage that art can bestow on them,
to recommend them to the just favour of the world.
And stones, however coloured, that are not attended
:
DIAMONDS AND PEARLS.
63
with specks, spots, fouls, stains or any other defects
to weaken their lustre, ought to have the utmost
skill of workmanship; and numbers there are, if
well-wrought, that would carry as much or more
vigour and spirit than many that do not fall under
that denomination; and therefore, if any made
stones appear susceptible of an improvement of
their lustre by being rectified, it is fit that such
should receive the benefit thereof, for the sake of
the pleasure and credit it must afford the owners,
and the reputation that such a conduct will bring to
this species of Jewels. And it is to be imagined,
that this will be thought worthy of some notice, as
the world seems so strongly disposed to value per-
fection in this Jewel, and none can be said to be so
that has any manifest imperfection of workmanship.
And here I shall take the liberty to observe, that
the truth of the manufacture of either, was never
brought under any stated rules of practice; nor was
there any recourse to be had to prove the truth of
the manufacture of any Diamond, till this treatise
made its first appearance, and for want of something
of this kind, there have been, in all times past, in-
numerable disputes amongst workmen, concerning
the true method of working Diamonds.
But this must be owned, that the fewest disputes
on this head have been found amongst those of the
best judgment; and, moreover, it is known that
their practice, when left to work agreeable to their
64
A TREATISE ON
own sentiments, has nearly been conformable to the
rules here advanced, and to which practice they
would have always adhered, if left at liberty; but
the selfish views of those they have wrought for
have obstructed it, and laid them under a necessity
of working according to the directions given them.
This has been the cause of so much defective work-
manship on Diamonds, and not only on middling
stones, but likewise capital ones.
This was the very cause of the largest Diamond
that ever appeared in Europe being wrought in a
deficient manner; which, if it be now as it came
out of the hands of those who wrought it, I take the
liberty to say, may be rendered complete; by which
means its form will be more comely and graceful,
its lustre greatly increased, and of course its value,
although its weight may be somewhat reduced; and
then it may be said to possess all the dignity that
Nature has favoured it with, and likewise that art
has done it justice.
The first fact I can make appear by two leads
cast from the stone; one when it was a rough Dia-
mond, the other when cut and polished; and the
second, how it came to be wrought as it was, I can
prove by incontestible evidence.
That this is the case of this and many other large
Diamonds is not to be wondered at; but rather
how those who had the direction of manufacturing
such stones, were influenced to submit to the loss
DIAMONDS AND PEARLS.
65
of so much weight, having nothing but conjecture
to direct their conduct; and their having left an
over-weight, must be owned to be an error of the
right side as that may be discharged whenever it is
thought proper; and it can scarcely be imagined
that any will be fond of retaining weight in a stone
that renders it ungraceful in its figure, and destroys
its life and vigour; especially as its expansion is
not lessened thereby, but will appear to sight larger
than before; which, perhaps, may cause a stone to
be deemed good that before was ranked in a lower
class. And, as it has been before said, such stones
will be worth as much or more, notwithstanding the
reduction of their weight, than when possessed of
their former weight by the remaining weight being
of a higher worth; so the expense of rectifying them
is the only loss that will be sustained.
The Use of the Sizes in Purchasing Rough
Diamonds.
AS the use of the sizes cannot but be sufficiently
seen in regard to wrought stones, they will
appear of equal use in regard to rough Diamonds,
inasmuch as they will assist the judgment concern-
ing the loss of weight that may be sustained in
66.
A TREATISE ON
2
working any Diamond; and therefore must be of
great service towards forming a right notion of their
value, as it is well known that some rough Diamonds
must sustain a much greater loss or diminution of
weight than others, arising from their peculiar
shapes. And to form a true judgment of the value
of any rough Diamond, the price or value of one of
a carat weight, similar to the stone which is to be
purchased, determines its value, as in the case of
manufactured Diamonds. But as it is more difficult
to judge what a rough Diamond will prove when
cut, than to judge of one manufactured, the buyer,
supposing him to be a merchant, must act with
proper precaution, and make sufficient allowance
to himself for the uncertainty of the stone answer-
ing expectation when wrought. And if it be a
stone of a considerable value, he must allow him-
self also for the interest of the money he lays out,
according to the time he supposes the stone may
remain unsold. These precautions are the only
means of guarding against the hazards and disad-
vantages that attend dealing in large rough Dia-
monds; and by such a conduct, dealers may be
enabled to sell at a price agreeable to the estimation
of the skilful; which estimation is the only thing
to be regarded by those who purchase them for
their own use. To urge any other considerations
to the purchaser for augmenting the price of any
Diamond beyond its just value, will, it is humbly
DIAMONDS AND PEARLS.
67
apprehended, be judged a weakness, and likely to
hinder the sale of such goods.
But, if it should be here remarked, that particular
cases or occasions may justify the seller in demand-
ing an advanced price for any Diamond, such de-
viations must be considered as merely occasional,
and the buyer is at liberty whether he will comply
or not.
Remarks on the India Manufacture of Diamonds
and their Custom in Regard to Rough Diamonds.
ALTHOUGH it has been supposed, under the
head of valuing Diamonds, that the India
people are acquainted with the principle of esti-
mating them, it will be now shown that they are
masters of no other essential parts of knowledge
concerning Diamonds.
* The Diamonds of India differ from the Brazilian; the
Indian are of a different specific gravity, and possess more lustre
and brilliancy, and consequently are more valuable than the
Brazilian. The supply from India has for many years been
gradually decreasing, and numerous places which formerly
produced large quantities of Diamonds have become totally
unproductive. From several Indian sources, at one time so
rich, producing Diamonds of great value in abundance, the
supply appears to have become almost entirely exhausted.
The defective knowledge of the Indian people, referred to by
Jeffries, has been considerably modified of late years. Civil-
isation has diffused light and knowledge.
68
A TREATISE ON
The manufacture of them they seem to know very
little of, as appears by the wrought stones that come
from thence, none of them being fit for use, and
therefore are always now wrought when brought to
Europe, which I shall describe as follows: they are
called lasks. They are in general ill-shaped or irre-
gular in their form at the girdle; their substance
or depth is ill-proportioned; some have more of
the stone's substance at the top than at the bot-
tom; their tables are seldom in the middle or centre
of the stone, and the collets the same; and some-
times the tables are of an extravagant breadth, and
sometimes too small; in the same manner are the
collets, and seldom horizontal; and their girdles
are often very thick and not level; the small work
very irregularly performed, and none are properly
polished; and the chief thing regarded is that of
saving the size and weight of stones; and this is
not much to be wondered at in them, as they are
unacquainted with the beauties of well-wrought
Diamonds. From hence it will appear that they
must be unqualified to judge of the true worth of
individual rough Diamonds. For instance: they
cannot know what a Diamond will lose in working,
to be well made; nor can they know, if a stone be
coloured, what degree of colour it will retain, or
what life and spirit a stone will carry well wrought;
all which they are very conscious of, and this makes
it very difficult to trade with them for single stones.
DIAMONDS AND PEARLS.
69
But it is not so difficult to trade with them for
parcels, because in them there are stones of all
shapes; and as some will lose more, some less,
they guess at that as well as they can; and so in
respect to their other properties, in which they are
not quite so much at a loss: and then they value
them by the lump, as they weigh one with another,
by the rule.
From whence we may see how necessary it is
for Europeans to be furnished with knowledge, as
by that means they must have some advantageous
opportunities in buying large stones, through the
ignorance of these people. Although it has been
shown how much regard they have to the saving
of weight in working of Diamonds, their attachment
thereto will farther appear, by the following custom
having prevailed time out of mind, the reality of
which seems not to be doubted.
The great people there employ a vast number of
slaves in search of diamonds: the small and
*It is a curious fact, that in Sumbhulpore the Diamond
washing is hereditary in two tribes, whose origin is unknown,
but who appear, from the traces of negro blood, to be descen-
dants of slaves imported by one of the conquerors of India for
that labour; they are called respectively Thara and Tora, and
possess sixteen villages in free Jhageer, or freehold; they now
number about 400 to 500 persons, working in the dry season
in the bed of the Mahanuddy, from Kunderpore to Sinepore.
The largest Diamond found there, since the transfer of this
country from the Mahratta to British rule, has been of eighty-
four grains. The quality of the diamonds is here distinguished
by the names of the Hindoo castes. The first quality is called
-
70
A TREATISE ON
•
middle-size Diamonds they sell, and some of the
large ones; but when they are fortunate in meeting
with a very large one, they lay it up as a treasure, to
aggrandise their family; and the head of the family
has a small, shallow hole drilled on the surface of
the stone, and when he dies, the next chief does
the same, and so from one to another—and the
more of these holes a stone has, the higher it is in
esteem, although such holes may prejudice it, if it
were to be manufactured; but as that is never in-
tended, they do not regard such prejudice, and
these stones are never parted with, let what will
happen; and if they foresee any ruin to the family
(as that sometimes happens in their further pur-
suit of Diamonds, which is very expensive, from
the vast number of hands they, employ in that
undertaking), in such cases they bury those stones,
so that they never appear again. For they cannot
bear the thoughts of any others having the posses-
sion of that which they have obtained at so great
an expense; and, it is said that, in consequence of
that custom, there are many very large Diamonds
irrecoverably lost, and likewise many that will never
be parted with.
Brahma, the second Kschetri, the third Bysch, the fourth Su-
dras. The weights used are the machas and the ruttee; the
machas consists of seven ruttees, and the ruttee is something
less than 2 carats weight." For this quotation we are in-
debted to Mr. Harry Emanuel, F.R.G.S., being an extract
from his work on " Diamonds and Precious Stones."
DIAMONDS AND PEARLS.
71
This custom is imagined to arise from their being
fearful of a Diamond losing its value, by losing
weight and magnitude in being wrought, which is
very true, as they work them, because they are
void of lustre, and therefore it is not an unreason-
able conduct in them, on that account alone; but
there is another reason assigned for it, which is,
the hazard their Diamonds are exposed to by their
manner of working: this is much greater than what
attends the working of Diamonds in Europe, for
they perform it in a rougher manner than is done
by the Europeans, more especially in respect to
polishing them; in doing of which they lay an
excessive weight on their Diamonds through un-
skilfulness (and for want of such curious machinery,
or mills, as are in Europe), which makes it not
practicable for them to give Diamonds a true polish.
Although this is the case in respect to the India
manner of working, there come now and then
stones tolerably well wrought and polished; but
these have been supposed to have been done by
Europeans, and upon their mills and skeves, and
to have been the property of such.
72
A TREATISE ON
Some Account of Authors who have heretofore
treated of Diamonds and Pearls, and the Im-
provements which have been made since their
Times.
THOUGH what I have advanced is really the
produce of many years' critical observation,
in the course of dealing in rough and polished dia-
monds, and has been a work of much time, labour,
and great expense, I am not a little pleased to
see it agree with what I have since found to be
mentioned by some celebrated writers, who have ·
exhibited the principle upon which Diamonds are
to be valued. The first which fell into my hands
was Monsieur Tavernier, who mentions it in his
"Voyages through Turkey, Persia, and the East
Indies," which he published in the year 1670, and
which were translated into English in the year
1678. The next was the memorable Mr. Lewis
Roberts, who published it in his "Map of Com-
merce," in the year 1638. Some time after, I
communicated the principle of valuation I have
exhibited in this Treatise to an acquaintance of
mine, who was a dealer and a Diamond-cutter, and
who had lived many years at Fort St. George in
that capacity; by whom I was informed, that the
India traders (meaning the natives of India) had
some established rule of estimating Diamonds, etc.,
which he believed to be the same with what I then
DIAMONDS AND PEARLS.
73
proposed. At length, several years after the pe-
rusal of the above writers, a still more ancient one
was shown me, by means of a gentleman of great
learning, and of great figure in the literary world.
This author was John Arphe de Villa Fane, who
speaks of the principle of valuation in his treatise.
entitled the "Standard of Gold, Silver, and Precious
Stones," published in Spanish in the year 1572, by
the King of Spain's especial licence. These writers
have mentioned some attempts to settle rules for
the manufacture of Diamonds; but, it is to be ob-
served, that not only what they have delivered is
very imperfect, but that when they wrote, the art
of making brilliants was not discovered; which
manufacture is essential to the saving of the weight
formerly lost, by cutting all rough Diamonds into
tables and roses; to prevent which loss of weight,
as much as possible, a heavy load of substance has
been left on both these kinds of manufacture.
Moreover, to save weight, rough Diamonds have.
been frequently sawed, especially such as had no
corners, in order to make them into roses; but this
practice was attended with a much greater expense
of workmanship, and withal, a much greater loss
of weight, than they have been subject to since the
making of brilliants has been introduced; this latter
manufacture being more suitable to stones of most
shapes.
These observations show, that if the truth of the
E
74
A TREATISE ON
manufacture of table and rose Diamonds had been
known in times past, which appears not to have
been the case, although it might have been of use
in preventing the past defective manner of making
them, it could not procure the advantages which
flow from the addition of the brilliant manufacture,
since that renders the whole a complete system;
and not only contributes to the greatest saving of
weight, but likewise ascertains the general loss of
weight, as has been already observed, which could
not be known till the manufacture was reduced to
settled rules. The want of this, probably, occa-
sioned a disregard of what has been taken notice.
of by these authors, concerning the manufacture
and valuation of Diamonds.
The next thing to be considered is Pearls.
i
PEARLS.
Of Pearls: their Perfections and Imperfections.
THESE jewels are next in importance to Diamonds,
as they constitute the next greatest share of
wealth of any other kind. The first thing to be
* The Pearl, from the most remote ages, has been considered
one of the richest gifts of Nature. In the sacred writings,
Pearls are frequently alluded to; as, for instance, in the Book
of Job, chap. xxviii, we are reminded that the excellency of
wisdom " cannot be valued with the gold of Ophir, with the
precious onyx, or the sapphire; the gold and the crystal can-
not equal it, and the exchange of it shall not be for jewels of
fine gold: no mention shall be made of coral or of pearls, for
the price of wisdom is above rubies." Another familiar in-
stance may be given, the kingdom of heaven being likened
unto a merchantman, seeking goodly pearls, who, when he
had found one pearl of great price, went and sold all that he
had and bought it. The ancient Persians, Egyptians, Baby-
lonians, and other Oriental nations, held the Pearl in great
esteem. The Romans regarded them as extremely valuable,
and they realised the most extraordinary prices. Pliny places
the Pearl next to the Diamond in value, and supposes the
former to proceed from drops of dew swallowed by the oyster.
In China Pearls are used as medicine-a belief existing among
Orientals of their great curative powers in various diseases.
The Pearl in Hindostanee is called "Moti." In Bengal, at
one time, virgins wore them on their arms as a preservative
of virtue. Seneca exclaimed against the shameful extravagance
of the Roman ladies in wearing Pearls. They termed a Drop-
Pearl "Unio," and wore a pair in the ear, just as ladies do at
the present day.
76
A TREATISE ON
observed concerning them is, that what beauty they
possess is the mere produce of nature, and that
they are not susceptible of any advantages or helps
by art- -a circumstance which recommends them
to the esteem of the world. Those of the finest
shape are perfectly round, which fits them for neck-
laces, bracelets, jewels for the the hair, and other
such like uses. But if a Pearl, of any considerable
size, be of the shape of a pear, it is not reckoned
an imperfection, because it may be suitable for
drops to ear-rings, solitaires, and many other jewels.
Their complexion must be milk-white; not of a dead
and lifeless, but of a clear and lively, hue, free from
stains, fouls, spots, specks, or roughness: such are
of the highest esteem and value.†
* Pearls vary in shape as well as in colour. Some of them
are of very curious form indeed, and will realise good prices if
found suitable for fancy articles. As regards colour, those of
a pure white are held in the highest esteem: the other colours
which some Pearls possess are pink, red, blue, yellow, green,
and grey.
Pearls possess great historical interest; and these beau-
tiful gems, when of large size and fine quality, are of great
value and realise high prices. Philip IV. of Spain, in 1625,
purchased one of the finest Pearls in existence called La Pere-
grina, and which, after passing through the hands of several
nobles, is supposed now to be in the possession of a Russian
princess. In proof of the value of Pearls we may mention the
fact that the Shah of Persia has a Pearl valued at sixty thou-
sand pounds, and the Truaum of Muscat has refused thirty
thousand pounds for one he possesses. The Empress of the
French has the finest Pearl necklace in the world-equalled
only by the one presented to Her Majesty by the East India
Company. The Marquis of Abercorn possesses a matchless
Drop Pearl of large size, and the Princess of Prussia was pre-
sented, on her marriage, with a very large necklace, but the
Pearls are unfortunately of inferior quality, and misshapen.
DIAMONDS AND PEARLS.
77
Pearls are defective when rough, spotted, or dull;
whether that be owing to any miscarriage of nature,
or to age, to wear, or any other accident; when
irregular in their shapes, be they flat or hollow,
craggy or gibbous; when they are stained with any
colour, as yellow, blue, green, red, brown, or that
of a dusky iron. It is also an imperfection when
they have large drilled holes, or are rubbed flat
about the edges of the holes by long use. These
defects cause a very considerable difference in the
value of Pearls, of the same weight and size.*
* The number of fine and large Pearls is exceedingly small,
and are found of almost every imaginable colour, and of the
most curious shapes-in some instances of considerable size,
but those of fine quality and large dimensions are very rare.
The Oriental Pearls are seldom found of any colour but yellow
and white, and are usually of a round shape, whilst the
American or Panama are generally blackish or brownish, and
principally long and drop-shaped. The wonderful polish of a
fine Pearl-which constitutes its value-has never yet been even
passably imitated, and appears to be caused by the friction of
the soft body of the oyster for a considerable length of time,
and this polish exists, in most cases, only on the outer skin, as
on removing the external surface the neat layers are invariably
dull in colour, and dead in lustre.
|
78
A TREATISE ON
Of the Rule of Valuing Pearis.
HE only rule of valuing them, is by the square of
THE
their weight, as in the case of Diamonds; nature
producing them after the same manner, viz., a vast
number of small ones, and progressively a less
number of larger, as they increase in size and
weight. Upon this principle two tables are formed,
of the prices of Pearls. The first eight contain
those of a carat weight downwards, of eight differ-
ent values, which will be found in Plates 17, 18, 19,
20, 21, 22, 23, and 24. The first being explained,
it serves for the other seven. The first column con-
tains the number of Pearls in an ounce troy, from
those of a carat weight to such as weigh but the 32nd
part of a carat. The second column contains the
progressive decrease of their weight, from those of
one carat, to those of the 32nd part of a carat. The
third contains their several prices, from one carat
at 2s. to those of the part of a penny. The
fourth contains the price of an ounce, at the rate of
2s. per carat, which makes £15, to that of the small-
est size, which is 9s. 43d.
3
The next thing to be taken notice of, is a table
that relates to Pearls, of a carat weight and upwards
to an hundred carats, which will be found in Plates
25, 26, 27, 28, 29, and 30. The prices of Pearls in
this table, are founded upon the supposition, that
the general price of Pearls, good and bad blended
DIAMONDS AND PEARLS.
79
together, is 8s. per carat; which will be found to be
the first article in it. This table, therefore, will be
of the same use with regard to Pearls, as the Dia-
mond table is in regard to Diamonds. For, if any
Pearl exceeds in quality, or falls short of those of the
middle sort, the rise or fall upon the price of a Pearl
of any weight must be so much per cent., as judg-
ment shall direct; which prevents all trouble of
finding it out by the rule. To show the convenience
of this table, the following example may be given.
If the value of a Pearl of 43 carats is required,
which may be supposed to be 10 per cent. better
than one of the mean or middle price, its price will
be found, by the table, to be £9 10s. 1d., then 19s.
is to be added, which is the produce of the 10 per
cent., and makes its value to be £10 9s. 1d.
To find out the first price by the table, reduce the
4 carats into eighths, which makes 39; then mul-
tiply 39 by 39, that makes 1521, the square of the
weight in sixteenths; therefore divide 1521 by 16,
that brings it again into grains, and makes 95; then
divide the 95 by 4, that brings it to carats, and
makes 23 carats, 3 grains, and of a grain; which
at 8s. per carat, produces £9 10s. 11d.
I 6
And as another method is introduced for finding
out the value of Diamonds, which is as applicable
to Pearls, the foregoing weight is made use of as an
example.
For instance, see what a Pearl of 47 carats comes
80
A TREATISE ON
to at 8s. per carat, which will be found to be 39s.;
so multiply 39 by 4, that makes 156s., or £7 16s.;
then add the value of of 39s. which is £1 14s. Id.;
cast up the two sums, and that will produce £9 10s.
1d.; so these two totals are alike, and agree in
price with one of that weight in the table; and that
being the price of one of the middle sort, the value
of the 10 per cent. must be added, which is 19s., so
the value of such a Pearl is £9 10s. 1d.
These instances are supposed sufficient to show
how much readier the value of any single Pearl is to
be found, by making use of the table; the usefulness
of which will appear in a stronger light, when it is
considered what number of occasions Pearls furnish
by their multiplicity, and likewise the small value
they are of individually, although not so regarding
their quantity.
N.B. Their value, compared with Diamonds, is
but as 8s. to £8.
As an application to the table appears to be by
far the readiest way of coming at the value of any
single Pearl, its farther usefulness will be shown in
valuing any parcels of Pearls.
For instance: suppose a parcel of Pearls (be
their number and weight what they may), and
various in respect to their qualities or goodness;
first, weigh the parcel altogether; when the weight
is known, count their number; when that is known,
see what the weight would be per piece, if they
!
DIAMONDS AND PEARLS.
81
were all of one weight, and then endeavour to form
a judgment what they may be rated at per carat,
as a mixed parcel; having settled that, see what a
Pearl is worth, of the weight you found they would
be of if they were all of equal weight or size, and
then value the weight of the whole parcel by the
price of that Pearl, and that will give the value of
the whole parcel. To illustrate this, suppose nine
Pearls of nine several weights, which may be of
different qualities or goodness, but being blended
together, they may be reckoned worth 8s. per carat.
As this supposed price agrees with the table, the
example will be drawn from thence, and will begin
with the first article therein, as underneath :---
Ist
2nd
3rd
4th
5th
7th
1 1 1 1 8
1
1
of
Carats.
Ι Ο Ο Ο
Ι Ο Ο
I 0 1 0
ΙΟ
I 1/1/0
I
I 11/0
I
8
00
BELLO O - -
0
1
8
1
8
2000
1
t
1
1
£ s. d.
68 0
O
Ο ΙΟ
O 12
1 1/1/0
6
0 15 1/1/0
O 18 O
I I
I
I
4 6
I 8 1
H H
I 12 O
The nine weigh 134 carats, and come to £8 9 6
The above nine Pearls, weighing 13 carats,
would make the weight of each 1 carat, the price
of which in the table is 18s., therefore multiply
E 2
82
A TREATISE ON
18s. by nine, the number of the Pearls, that makes
162s. or £8 2s. od.
The value, rating them by their several weights,
as above, makes the total £8 9s. 6d., which is
7s. 6d. more than by the other method of valuing
them; and this arises from the loss of fractions in
that case, and although that be something in this
sum, it is not worth regard in a larger sum, which
will be the same when Pearls are rated at 8s. per
carat, and for farther satisfaction the following case
is inserted:—
Carats.
Ist
of
6000
2nd
600 A
8
3rd
4th
5th
6th
7th
8th
9th
t
1
8
600
бо
6 ㅎ
​6 금
​Hez Haz Hlaz -laz
O
6 2/3/20
7 0 0 0
The nine weigh 58 carats,
I
·
1
I
£
s. d.
14
8 0
15
8
15 12 6
16 5
16 18
17 II
11
О
I 1/1/
6
18 4
18 18 1
19 9 6
£152 9 6
The above nine Pearls, weighing 58 carats,
would make the weight of each 6 carats, the price
of which in the table is £16 18s. First, multiply
nine by £16, that makes £144; next, multiply nine
by 18s., that makes £8 2s., add these two sums
together, the total will be £152 25., which is 7s. 6d.
short of the above sum of £152 9s. 6d. But if the
DIAMONDS AND PEARLS.
83
number of articles had been more, and the price of
any parcel of Pearls should be higher, it can but
little increase the difference, and therefore it is not
worth regarding, more especially when it is con-
sidered, that none can judge the value of any one
Pearl or parcel, to any such-like nicety. As to
what has been said of the convenience of this table,
the same might have been said of the Diamond table;
but as there seemed not to be the like necessity for it,
in regard to Diamonds, it has hitherto been omitted,
and the rather to avoid repetition.
As the convenience of this table is evidently
shown, it may be proper to observe, that in making
use of that, or either of the other methods for find-
ing the value of Pearls, the highest price of any
Pearl of a carat weight cannot be valued at more
than 16s., when the price of the middle sort of that
weight is valued at 8s., nor those of the lower sort
of a carat, at less than 2s., because all of a baser
sort deserve not to be considered as Jewels. And
this, probably, will be thought scope enough to em-
ploy speculation and judgment; notwithstanding
which, it is to be supposed, that all who are skilful
will agree in sentiments concerning the value of
any Pearl of a carat weight, however circum-
stanced, as nearly as in the case of Diamonds, as
the value of Pearls if any weight is to be deter-
* The beauty and value of Pearls depend on their colour,
form, texture, transparency, and lustre. To be perfect a Pearl
84
A TREATISE ON
mined by the price of one of a carat weight similar
in all circumstances; or, as was said of Diamonds,
the same may be said of Pearls, that every Pearl
is to be valued as it is worth per carat, by the rule
of estimating.
N.B. It is to be observed, that what is supposed
of judicious Jewellers agreeing in their sentiments
to five or ten per cent. concerning the value of any
Diamond or Pearl of one carat weight, by which
the value of a Diamond or Pearl of any weight is
to be determined, is to be understood to relate to
the natural and just value of them only; and when
there is a compliance with any other price, that
must be considered as the occasional price; and if
persons who buy for their use, could be assured
what is the just price of any Jewel, it would be the
means of influencing them to give the value of
them. And this must necessarily facilitate the
transaction of this business, and I am humbly of
opinion, if this had been the case in times past,
must be perfectly round, or drop-shaped; it must be of a per-
fectly pure white colour; it must be slightly transparent, free
from specks, spots, or blemish, and possess the peculiar lustre
characteristic of the gem. The value of drop-pearls is difficult
to estimate, and the prices vary so greatly according to size
and quality; but it may be mentioned that perfect white drop-
pearls of 80 to 100 grains, may be estimated at from £7 to £11
per grain; those of 50 to 80 grains, at from £4 to £7 per grain;
and those of 30 to 50 grains, at from £3 to £5 per grain;
smaller sizes bring from £1 to £3 per grain. Misshapen pieces
are often sold at per ounce, the price varying from £10 to £200
per ounce, according to size, quality, and colour.
DIAMONDS AND PEARLS.
85
many capital Jewels, which have lain many years
in the hands of persons who bought them in order
to make profit of the money laid out, would have
found purchasers of them long ago, to the advan-
tage of their present owners.
As so much depends on traders being masters of
the most complete knowledge of this business, it
must be supposed they will not be wanting in im-
proving themselves therein by all means that may
be procured, as it will render them a beneficial
body to the rest of mankind, and, of course, raise
their characters, which have heretofore lain under
disagreeable imputations.
Here it may be proper to observe, that whatever
knowledge persons may have of the just value of
Jewels, it will not exempt those who buy them for
their own use from sustaining a loss in purchasing
them; but it will lessen the losses that might other-
wise happen, which the world has heretofore been
subject to for want of such knowledge. That losses
must be sustained is unquestionable, and that these
must vary as circumstances differ, the following
cases will evince.
86
A TREATISE ON
3.
Observations on the Losses supposed to be
sustained by the Purchase of Jewels.
THE expense of making some pieces of jewelling
work comes to a considerable part of the pur-
chase money; and generally where there is the least
value of Diamonds, the expense is the greatest, as
when a large number of small Diamonds are em-
ployed; when such a Jewel is re-sold, that expense.
must be deducted, if it be injured by wear or by
accident, or it becomes unfashionable.
Again, Jewellers must be supposed to have a
considerable sum of money employed in trade, the
returns of which are not very frequent; and, there-
fore, a loss must unavoidably attend the purchasing
Jewels, and the greater in buying large Diamonds,
although the expense of setting them be less on
account of their lying much longer in the posses-
sion of Jewellers than those of the smaller sort;
and, therefore, all Jewellers, supposing the pro-
bability of this, never give so near the value of
them as for smaller stones, they being always more
marketable.
As this is the case, persons of rank and fortune,
that need not regard any reasonable loss, or the
interest of money, are the proper purchasers of
Jewels; and the money laid out by such persons
* Pearls are much more generally worn on the Continent
than in this country, some of the commonest description being
DIAMONDS AND PEARLS.
87
can no more be deemed luxury in them, than that
which is expended in equipping and furnishing side-
boards and cabinets, and on all other costly personal
equipments in gold and silver. But it may be said,
that the latter is more useful and necessary than
the former; to which it may be answered, that its
uses may be supplied at a much cheaper rate; so
the appearance and credit must be the remaining
motive for laying out money that way, which is the
same in respect to Jewels; and if the losses attend-
ing the purchasing these be an objection, it will be
found to lie as strong against the other, in respect
to fashionable elegant things, the workmanship of
which, upon an average, comes to at least one-
fourth, if not one-third, of the purchase money.
sold very extensively in the south of Germany, Russia, and
the Danubian Principalities, where they are worn by the pea-
santry, and are greatly valued by them. Pearls deteriorate by
age, and by contact with acids, gas, and noxious vapours of
all sorts. Various means for restoring them to their original
beauty have been tried, but have been found useless, and cal-
culated to still further injure them than to restore them. The
best way to preserve Pearls is to wipe them with a clean linen
cloth after being worn, depositing them, carefully wrapped in
linen, in a closed box. The operation of boring Pearls should
be performed slowly and with great care, so as to avoid the
risk of breaking them. The natives in India are very expert in
this particular, the holes there being drilled much smaller and
more straight than is accomplished in this country. In the
Exhibition of 1862 a curious article was shown in imitation of
Pearl. It was made of mother-of-pearl, in the form of a straw-
berry, and was sold to an English merchant for a ridiculously
exorbitant price, its intrinsic value being comparatively trifling.
88
A TREATISE ON
The loss by Jewels, it is humbly apprehended,
will not, in future times, exceed that, although it
has been otherwise in times past, as appears by
instances that have been given; which show that
not above one-third or one-fourth of the purchase-
money could be obtained for Jewels, either by way
of pledge or sale; which has chiefly arose from
jewellers not being well acquainted with the natural
and just value of them, which cannot be the case
in future times; it being evident that traders have it
in their power to come at their true value, by
estimating them as they are worth per carat, by the
rule exhibited. This being the case, anyone else
may attain the knowledge of the value of any
Diamond or Pearl, or parcels thereof, by applying
to a skilful jeweller, to know what they may be
worth per carat.
And this will be the means of preventing any
persons selling their Jewels on such disadvantageous
terms, as have been before taken notice of, since
they will rather pledge them, and wait for a more
favourable offer; and a better knowledge of their
value will procure more money lent on them, if
occasion requires it, than in times past. And as
the skill of traders appears so useful, they must be
supposed to be entitled to a suitable reward, for
giving their opinions in all such cases. These
measures will tend to support the worth of Jewels,
and render all property of this kind permanent
DIAMONDS AND PEARLS.
89
wealth, exclusive of the deductions a little before
mentioned, and make them the proper possession of
persons of rank and fortune here, as well as in other
countries-especially if the wealth of the nation
increases; because all purchases of income must
advance as that augments, and of course brings
down the value of money.
For example, if any one should be forced to give
three hundred pounds for an income, that in time
past could be purchased for two hundred pounds, it
is evident that then three hundred pounds is reduced
to the value of two hundred. If this be an evil, the
laying out the exuberance of our money in Jewels,
seems to be the properest redress of it, as they are
a durable, though not a profitable, treasure; inas-
much as they may be found of convenience in any
time of distress, whether private or public. The
latter, indeed, we have the happiness to have no
reason to fear.
What has been observed of the utility of Jewels,
Diamonds especially, to persons of dignity, and
those of different fortunes; and of the conduct of
the India people, in not forcing the sale of them, by
lowering their price, but, on the contrary, withdraw-
ing them when there appears a slack demand,
which is supposed to arise from the great expense
they are at in the search of them; for although the
price of labour in India is excessively cheap, yet
the hands that are employed in this work, as
90
A TREATISE ON
Monsieur Tavernier and other authors have taken
notice of, are so very numerous, that it makes it a
costly, and even a precarious undertaking; and con-
sidering that, notwithstanding Europe has been
supplied with Diamonds from thence, and from the
Brazils, within twenty years last past, abundantly
more than in any preceding number of years; yet
the amount of the annual value of them, on an
average, comes a great deal short of two hundred
thousand pounds sterling; and, further, considering
that many countries are come more into the use of
them, of late years, than formerly, and that some,
which in times past, were almost strangers to their
existence, are now buyers of them, but principally
the most indifferent sort, which is a beneficial
circumstance, as the taste of other countries, which
I need not name, is so much refined: all these cir-
cumstances taken into the account, and supposing
the Brazil mines prove abortive, cannot but abate a
suspicion that has been entertained concerning
this part of the world being glutted with Diamonds,
which it is thought by such persons, will in time
sink the price of them.
Judging these considerations are sufficient to quell
such fears, I shall proceed to show it is not the
case at present, their price of late being advanced
(I mean in Europe only), and the cause of it is this:
that most of the capital Jewels are returned into the
possession of their proper owners, which have some
DIAMONDS AND PEARLS.
91
years past been in the hands of usurers, owing to
the great expense that some princes have been at
in the late war; which the peace has not only
enabled them to redeem, but likewise qualified them
to become farther purchasers. And this proves the
fitness of pledging Jewels rather than selling them
below what they ought to fetch, supposing that
necessity does not force any thereto; which is not
to be imagined of persons of high rank, or of good
estates, as time gives them an opportunity of
redeeming any pledges.
CONCLUSION.
THIS concludes the important subject I have been
treating of; and the enlargements that have
been made to this edition, I flatter myself will be
found not only explanatory of my first publication,
but that they will likewise give force to what is
therein contained, and which would have been added
thereto, had I then seen it to be necessary; but
which I have not been convinced of till lately, and
now think the omission of it would be an impedi-
ment to my design, which is that of communicating
'truth and knowledge, beneficial to the public, and
to all ingenious traders, and which is calculated to
raise their reputations and usefulness, and likewise
to promote art in the embellishments of Diamonds,
and recover, if possible, the almost lost manufacture
of them to this kingdom, that has in time past been
possessed of the chief share thereof, and which has
carried the improvement of it to the greatest height
of any part of the world, and is now as capable of
doing so as ever, if permitted; which I hope to see
brought about.
DIAMONDS AND PEARLS.
93
The loss of this valuable manufacture, and of the
trade resulting therefrom, has been wholly owing to
a delusive manner of working them abroad, which
enables foreigners to sell 'Diamonds cheaper by
weight than it is possible to afford well wrought
ones for. By this means they are become pos-
sessed of almost the whole of this manufacture and
trade.
And this practice has been much countenanced
by some traders in London, who have sold for some
years past three-fourths or more of these foreign
wrought Diamonds, to the great discredit of their
wearers; which conduct seems to come but little
short of an affront on the quality and gentry of this
kingdom, and shows a manifest disregard of the
interest thereof; which I am sorry to have occasion
to take notice of, as well as of some other matters
that could not justifiably escape my observation,
but which I am satisfied will give no offence to any
impartial unprejudiced person; and the new matter
in this edition, I doubt not, will meet with the
approbation of the judicious, as it must give an
additional enforcement to what is contained in the
first, and serves to render these important articles
of wealth of more established worth than in timės
past, since their value appears to be determinable
by rules founded on reason and truth, which has
hitherto been subject to the capricious estimation
of unguided judgment. And I am the more
94
A TREATISE ON
encouraged to hope for the countenance of such
persons, as my first has received that honor, as
well among people of rank and condition, as among
traders in Jewels; and I have the satisfaction of
knowing it daily gains ground, and am particularly
pleased in finding a considerable increase of busi-
ness within twelve months past, in the best manner
of working Diamonds.
And now being no ways conscious of having
taken any unwarrantable freedom in any part of
this treatise, but pursued truth, justice, and the fit-
ness of things to the best of my knowledge, I shall
not trouble my readers with any farther vindication
of my conduct. But in respect to any imperfection
of style that may appear in this treatise, I hope the
candid part of the world will overlook it, as I make
no pretension to any accomplishment in that way,
and all that I have aimed at has been to convey
my thoughts in as clear a manner as my abilities
would enable me to do: and this, I question not,
will be accepted as a sufficient apology for any in-
accuracy of expression in the Book.
DIAMONDS AND PEARLS.
95
1
The expence of making The expence of making
full-proportioned bril-
liant diamonds.
spread brilliant dia-
monds.
Carats.
Per Carat. Carats.
Per Carat.
d.
l. s. d.
I
1 2 3
l. s.
I
I
I
I
4
5
IO
15
20
I O O
2 6
5
7 6
I IO O
2 2 6
2 15
3 7 6
5
IO
I 5 O
1 8
1
I II 3
I 14 4
I 17 6
2 13 I
389
4 4 4
5. o O
5 15 7/1/0
6 II 3
7
8
6 10/1/20
2 6
8 18 1
9 13 9
IO 9 4
II
12
5 0
0 71
12 16 3
13 II 101
14 7 6
15 3 11/1/0
15 18 9
O
15
20
25
4 0
25
30
4 12 6
30
35
5 5 O
35
40
5 17 6
| | | | | | | | ││││
1 2 3 4 5
40
45
6 10 O
45
50
726
50
55
7 15
55
60
87 6
60
65
9 0 0
65
70
9 12
6
70
75
10 5
75
80
10 17 6
80
85
II IO О
85
| | | | | | | |
go
12 2 6
90
95
100
12 15 O
13 7 6
95
ΙΟΟ
16 14 4
96
DIAMONDS AND PEARLs.
The expence of making The expence of making
full-proportioned rose
diamonds.
spread rose diamonds.
Carats. Per Carat. Carats.
I
1 2 3
4
O 15
0
16 101/20
0 18 9
I 0 7/1/2
1. s. d.
I
5
I
2 6
ΙΟ
I II 10
15
2
I 3
20
2 10
7/1/
20
25
3 0
O
25
30
3 9
41
| | | | | | | | | │
4
123 +50
ΙΟ
15
30
35
3 18 9
35
40
4 8
40
45
4 17
6
45
S.
Per Carat.
1.
d.
0 2
о
O
6
I
I
I 5
O
I 7 6
2
I IO O
2 6
2 15 O
3 7 6
400
6
4 12
5 5
5 17 6
6 10
O
50
5 6 101
50
7 2 6
55
5 16 3
55
бо
65 71
60
65
77∞∞
70
6 15
7 4 4
O 65
70
75
7 13 9
75
80
85
8 3 1
8 12 6
80
O 50 IN O
7
7 15 O
8
6
9 0
0
85
90
95
9 I 10/10
9 II 3
90
95
JOO
10 10 71 100
| | | | |
9 12
ΙΟ
5
IO 17
II IO O
12 2 6
12 15
O
15 7 6
6
1
2
a
5
a
a
9
7
Z
a
9
T
h
9
7.
1
.3
4
6
4

1
2

The Size of Brillant Diamonds.
Number Weight|| Number Weight Number Weight
13
34
3
22
7
2
18
14
J
3
1/3/
23
72
4
5
15
44
27
16
12
เง
2
25
り
​17
4/3/
7
24
9
2½
18
5
23
19
52
3
20
11
34
12
ནས་
ذا
21
62
26
27
10
24
122
ت
3

Brillant Diamonds.
Number Weight Number Weight
29
14-
35
24
30
1522
36
26
31
32
17
183
37
28
38
30
33
20
33
34
22
39
୦
O
4

Brillant Diamonds.
Number Weight|| Number: Weight
40
36
44
50
41
39
45
54
72
42
46
O
о
58
73
46
47
62

5
No
Brillant Diamonds.
WtNo
18
49
50
51
O
о
Wł
66
52
55
70
53
90
75
54
95
80
55
100
6

3
7
ནཱ། །

The Sizes of Rose Diamonds.
Number Weight || Number Weight||Number Weight
7
2
3
13
3
22
ク
​4
Fif
14
23
72
1
~~
15
44
24
8
18
76
42.
2
17
43
25
7
24
9
8
2/1
70
5
26
10
9
23/0
19
53
10
3
27
11
20
6
11
34
28
12/
27
622
12
3}
8

Rose Diamonds.
number Weight Number Weight
29
14
35+
24
30
15½
30
26
31
17
37
28
32
182
38
30
33
20
34
22
39
33
9

Rose Diamonds.
Number Weight|| Number Weight
40
36
44
50
41
39
45
54
42
42
46
58
43
46
47
62
10

No
Rose Diamonds.
W t
люб
Wł
48
66 52
85
49
70
53
90
50
75
54
95
51
80
55
100
.1
11

The Tables of Diamonds.
Nt Price Wt Price Nt Price
Cr £ s d Cr £c s d Cr £es d
1
8:0:0
3/
105:2:6
64
312 :10:0
16
10:2:6
3 9/9/9/0
112 10:0 68
325:2:6
14
12:10:0 37
120:2:6 67
338:0:0
13
15:2:6 4
128:0:0 6 351:2:6
12/12/2
18:0:0
4ㅎ
​136:2:66
364:10:0
18
21:2:644
144:10:0 67 378:2:6
19
24:10:0
4 3 3 3
153:2:6 7
392:0:0
1/3/ 28:2:6
4 2 162:0:0 76
406:2:6
2
~ ~ ~ ~
too six majoo you 40/20 coli noo
32:0:0
435/55
171:2:6 74
420:10:0
2호
​24
2 3/
2÷
24
N N
36·2:6 43 180:10:0 73
40:10:0 43 190:2:6 7/2/2
45:2:6 5 200:0:0
732/
50:0:0 53 270:2:6
55:26 54 220:10:0 7%
2章 ​60:10:0 53 231:2:6
2/17/
CO N
3
66:2:6 5½
496:2:
6
8
512:0:0
242:0:0
86
528:2:6
72:0:0
535385
253 ·2:6
84
544 10:0
264·10:0
8 9330
561.2.6
34
8
84:10.0 5/1/2 276:26 8 2/3/1/1
578·0:0
33
97:2:66
288:0:0 83595:26
3 ½
98:0:0
63
300·2·683
612:10:0
37 78:2:6 5
435:2:6
450:0:0
73465:2:6
480:10:0
12

Diamonds continued
Wt Price Wt Price Wt Price
Cr £ s d Cr £ s d Cr £ p d
87
فل
630:2:6 11½ 1058:0:0 14% 1596:2:6
648:0:0 11/15/ 1081:2:6 144 1624:10:0
9
9급
​666:2:6
9 #
684:10:0
77-3
11/7/
1704:10:0 748 7653:2:6
7128:2:6 14 ½ 1682:0:0
9 3 703:2:6 72
1152:0:0 14 1771:2:6
7
9ž
722:0:0 123 1176:2:6 143 1740:10:0
98998505
71:2:6 724
1200:10:0 143 7770:2:6
9
760:10:0 72-3/30
1225:2:6 15 1800:0:0
93
780:2:6 723/
7250:0:0 15 1830:2:6
10
800:0:0 12
1275.2:6 15 1860:10:0
10/3/
820:2:6 723
1300:10:0 153 7897:2:6
10
840:10:0 12/3/
70/31/ 867:2:6 13
1326:2:6 1522 1922:0:0
1352:0:0
15 1953:2:6
10글
​882:0:0 73 1/1/
1378:2:6
153 1984:10:0
70%
903:2:6 137
1404:10:0
153 2016:2:6
103 924:10:0 | 133 | 1431:2:6
76 2048:0:0
10%
946:2.6 13½ 1458:0:0
16%
2080:2:6
77
968:0:0 || 133 | 1485:2:6
767
2112:10:0
11's 990:2:6 132 1512:10:0
163
16층
​2745:2.6
114 1072:10:0
1331540:26
162
2178:0:0
11-3/31/ 1035:2:6
14 1568:0:0
168 2271:2:6
13

Diamonds continued.
Wt Price Nt Price W Price
Cr £s d Cr £os d Cr £os d
763/
3
2244:10:0 19 3003:2:6 22 3872:0:0
16% 2278:2:6 192 3042:0:0
| |
17
2312:0:0 | 193 | 3081:2:6
772346:26 193 3120:10:0
22% 3976:2:6
22 3960:10·0
22 40052.6
| |
174 2380:10:019 3160:26 22
4050:0:0
224095·2·6
3240:26 22 4140:10:0
172485:26 204 3280:10:0 22 4186:2:6
17
2415:2:6 20
3200:0:0
17½
2450:0:01 20 1/1/
17
2520:10:0 203
3321:2:6 23
4232:0:0
17
2556:2:6 20½
3362:0:0
23% | 4278:2:6
18
2592:0:0 20
€
3403:2:6
234 | 4324:10:0
18%
2628:2:6 203
3444:10: 0
23% 4377·2·6
23 4418:0:0
18
2707:2:6 21
3528:0:0 235 4465:2:6
18 | 266410:0 || 20% | 3486:2:6
18½ 2738:0:0 211 | 3570:2:6
3570:2:6 232 4512:10:0
18% 2775.2:6 274
183 2812:10:0 21
187 2850:2:6 21
19 28880 0 213
19 2926.2.6 21
19 296470:0 27%
3612:10:0 23% 4560:2:6
23급
​3655:2:6 24 4608.0:0
3698·0:0 24% 4656.2.6
3747:26 24 4704:10:0
3784·70·0 248 4753:2:6
3828:26 24 4802·0:0

14
Diamonds continued.
Wt Price Wt Price Wt Price
Cr £s d Cr £o s Cr £o s
24 4851:2:6 292
6962:0
34 9660:10
25
24 4900:10:0 | 293
24% 4950:2:6 30
5000:0:0 30
7080:10 35
9800:0
7200:0
7320:10 35½ 10082:0
354
9940:10
25号
​5100:10:0 30%
252
5202:0:0 30%
7442:0 35 10224:10
7564:70 36
10368: 0
25
5304:10:0 31
7688:0
36 10572:70
26
5408:0:0 31
7872:10 36½ | 10658:0
263 5512:10:031
7938:0
364 10804:10
2625618:00 313
8064:10
3710952:0
26
5724:10:0 32
8192:0
37411100:10
27
5832:0:0 32
8320:10
37½ 11250:0
27% 5040:10:0 32
8450:0
37
11400:10
2732 6050:0:0 | 323
8580:10
38 11552:0
27 6160:10:0 33
8712:0
3811702:10
28
6272:0:0 337
8844:10
383/2
11838:0
282
6384·10:0 | 33½ 8978: 0
3812012:10
28/ 6498·0:0 333
9112:10
28/3/ 6672.10.0 34 9248:0
29
6728:0:0 343 9384:10
20 6844:10:0 342 9522:0
39
12768:0
39412324:10
393 | 12482:0
3
39 12640:10

15
Diamonds continuedo.
Wt Price Nt Price Wt Price
Cr £ s Cr
40 128000 45%
404 12960:10 45½
£es Cr £
51 20808
21218
16380:10
16562 0 51%
401 13122:0 | 45%
16744:10 52
21632
403/
13284.10 46
16928:0 522 | 22050
47
13448: 0 | 46±
17112:10 53
22472
414 13612:10 4612
17298 0 533 | 22898
412
137780462
17184 70 54
23328
41 13044:10 47
17672054
23762
42
24200
43
14112:0 474 | 17860:10 55
|
424 | |
14280:10 47½ 18050: 0 55½ 24642
|
423 144500 47218240:10 56 25088
42% | 14620:10 | 48
14792:0 484
18432 056 | 25538
18624:10 57 25992
43
4
14964:10 48%
7
18818:0 57½ | 26450
43 ½-½
15138: 0 483
432/
15312 10 49
44
154880 49i
10012:10 58 26912
19208:058½ 27378
19404:10 59 27848
444 15664:10 49½
196020 59% 28322
44½ || 15842·0
493
19800:10 60 28800
41
16020:10 50
20000 0 60% 29282
45
16200: 0 50ž 20402:0 61
29768
16

Diamonds continuedo
Wt Price W Price W Price
Cr £
Cr £o| Cr £o
61½ | 30258 72 41472 90 64800
62 30752
72ź
42050
91
66248
622/
37.250
73
42632 92
67772
63
37752
73ź
43218 93
69792
637 32258
74
43808
94
70688
64
32768
742
44402 95
72200
642
33282
75 45000
96
73728
65
33800 76 46208
97
75272
65½
34322 77
47432 98
76832
66
34848 78
48672
99
78408
66ź
35378
79
49928 100
80000
67
35912
80
51200
671
36450
81
52488
68
36992
82
53792
682/
37538
83
55112
69
38088 84
56448
69z
38642 8.5 57800
70
39200 86
59168
70%2
30762 87
60552
71 40328 88
61952
•
712
40898 89
63368
77

The Tables of small Pearl.
The Number
of Pearl
in an Oz Froy.
Their Value Their Value
Their
Weight
s
P. Piece P. Ounce
at 2 p. Carrat at that Rate
No
6
Cr
750
160
171
184
1
15
76
14:7:3
1:63
8
13:1 : 10/1/
72:2:774
s d£ s d
2: 0
1:932
1: 932
15:0:0
200
3
4
17
278
240
266
300
342
400
480
boo
800
1200
16
晋
​2-2
32
1 1/2
3
8
18
Die No 2/0 cold 5/20
7
ть
8
~/or N/ÃO 3/0 6/10 y/o m/ão 0/00
1:32232
1:12
11 322
ク
​19
7392925
6
4 32
19
3
3 -0
11:5:0
10:6:01/08
9:7:6
8:8:348
7:10:0
6:10:1176
5:12:6
4:13:9
3:15:0
72222 2:16:3
1:17:6
2400
71/6
18:9
4800
7
32
1928
9:47/2/2
18

Small Pearl continued.
The Number
Their Value Their Value
Their
of Pearl
in an Oz. Triny Weight at 4 p. Carrat at that Rate
4. Piece D. Ounce
No
Cr
s d £ s d
150
160
777
75
76
7
4:0)
30:0:0
2/0 0/00
3:63
28:2:6
3:01
26:3:84
13
184
76
2:7
24:5:102
200
2:3
22:10:0
278
1/6
1:10 1/6
20:12:1궁
​240
266
300
312
400
480
600
800
5
8
1:6-3
18:15:0
4
9
ть
1:33
금
​7/6
NOU NÃO opo
1:0
16:16:7/½
15:0:0
9 3/3/6
13:7:70/4/
6 3
77:5:0
4
4. $
9:7:0
3
77
1 1/
7:10:0
7200
2400
1/6
4800
13322
3
m/x mião mi
5:12:6
3:15:0
1:17:6
18:9

19
Small Pearl continuedo.
in an
The Number
of Pearl
Z
Their
Oz Troy
Their Value Their Value
P. Piece 4 Ounce
Weight at op. Carrat at that Rate
No
150
6.r
sd.
£s d
1
6.0
45·0:0
15
160
16
5:3 32
42:3:9
7
171
8
13
184
2010
4.
218
ть
5
240
266
300
312
400
480
600
800
1200
2400
4800
No monio No You Nije oni 1/10 NT GO/A0 NO NÃO Many
4:78
34·5:63
3:11 2
17
36:8:9-3/4
32
3:42
33:15:0
2:10 32
30:18:2.13
73
76
2:4. ㅎ
​28:2:6
1:10 - 20592
25.4.11/
32
1:6
22:10:0
7
16
1:1 23/32
25
8
10/
10 8
19:12:93/6
16:17:6
7 32
74:1:3
76
7
4
4 7/47
3
2 52
32
1 //
Nivala No va
11:5:0
8:8:9
5:12:6
323
2:16:3
32
128
1:8:17
20

Small Pearl continued.
Their Value Their Value
The
Number
of Pearl
in an Oz Froy
No
150
160
777
184
200
Their
p. Piece
Weight
at
& g. Carral
f. Ounce
at that Rate
6r
s d
£s d
1
218
7/6
240
266
300
342
400
480
600
800
1200
210 ya monix 5ão 50/60 ayo Ny MAO 3/00 53/20 siqi milo ale
8:0
7:0층
​60:0:0
56:5:0
3
6:1 1/2
52:7:43/
13
76
5:3:3
48:11:9
3
4
4:6
45:0:0
3:9층
​47:4:33/
3:1 ½
37:10:0
2:67
2:0
7:63
33:13:3.3
30:0:0
26:3:84/
1:7 3
22.10:0
9 8
18:15:0
4
6
15:0:0
3
3 3
11:5:0
1
7:10:0
2400
166
3:15:0
4800
32
933528 7:176
21

Small Pearl continuedo
IN AN
The Number
of Pearl
Z Trcy
Their Value Their Value
Their
P. Piece
Weight at top. Carral
އ
P.Ounce
at that Rate
Vo
Cr
s d
£ s d
750
15
160
76
171
184
200
218
240
266
300
342
400
480
600
73
76
CO NO NO mid 50 60
3
10:0
8:91592
7:7 공
​6.7 32
7
5:7 2
75:0:0
70:6:3
32
65:9:28
60:14:84
56:5:0
4:823
51:10:4끎
​32
3:10 7/
a
16
3:1 32
31
4
77
76
8
7
miec w/o sit apo ~/00
2:6
7:10 31
32
46.17:6
42:1:7-
37:10:0
32:14:79/6
7:43
28:2:6
17 322
23:8:9
7
2
18:15:0
4 32
14:1:3
7
1 %
7
9:7:6
2400
76
15
32
4800
32
15
4:13:9
2:6:707/2
728
800
1200
3
78
8
22

Small Pearl continuedo
The Number
of Pearl
in an Oz Troy
Their
Their Value Their Value
Weight
P. Prece
P.Ounce
at 12 p.Carrat at that Rate:
No
6.r
s d
£sd
150
160
171
184
200
218
240
266
300
342
400
480
600
15
16
Ala atler 0:00 ale nie ako o/a al/a A/co aică color
12:0
1
90:0:0
10:69
84:7:6
76
9:24
78:11:0
16
7:17 16
6:9
5.876
4:8 금
​3:9 3/6
3:0
2:3 -1/6
ть
7:8 4
7
7:2:76
9
72.77:72
67:10:0
61:16:55/
56:5:0
50:9:113/
45:0:0
39:5:63
33:15:0
28:2:6
22:10:0
800
16
5 76
16:17:6
1200
7
8
2 4
71:5:0
2400
7/6
5:12:6
4800
325
2:16:3
64
23 ·

Σ
Small Pearl continuedo.
Their Value Their Value
200
218
.240
266
300
542
400
480
600
800
1200
ठ
2400
1/6
4800
210 000 03/10 3/4 5/10 1/0 0/0 y/o no 3/0 0/0 1/4 3/10 7/ Yo Yo
76
7
79
16
The Number
of Pearl
Their
P. Piece
Pounce
in an & Froy Weight
in
No
150
160
777
184
at
is
Carrat at that Rate
6.r
s d
£ s d
1
15
14:0
12:3-32
105:0:0
98:8:9
10:8 흥
​91:12:10/7/
9:2:22
85:0:64
32
7:10:2
78:15:0
71
-
76
6:7:32
13
72:26
5
5:5:8/
4:5:32
65:12:6
2
3:6
7
2:8 32
5
45:16:51/0
1:1 응
​39:7:6
7:413
32:16:3
32
10 1/
26:5:0
76
5 224
29
32
19:13:9
2 /
13:2:6
27
32
6:1:3
32
27
728
3:5:72
58:18:39
52:10:0
24

Small Pearl continued.
The Number
Their Value Their Value
Their
of Parl
inan Oz Froy Wight at 18 & Carrat at that Rate
f.
#Piece
P. Ounce
لة
No
로
​sd £sd
150
160
177
75
76
1
16:0
120:0:0
184
76
200
218
240
266
300
342
400
10/10 7/0 0/100 5/10 40:00 0/0 Nov 7/10 3/00
14:03
112:10:0
8
12:3
104:14:9
73
10:6 3
录
​97:3:6
9:0
90:0:0
71
16
67:6:72
4:0
60:0:0
3:0 $
52:7:4
2:3
45:0:0
480
1/
1:6 2/4
37:10:0
600
4
1:0
30:0:0
800
1200
7/6
2400
4800
32
76
3/10 ~100
6 3/
22:10:0
7
3
15:0:0
76
7:6 3/
6:3
5:03/
75:0:0
82:8:77
only majo
3
76
7:10:0
3:15:0
25

The Tables of large Pearl.
Wt Price Wt Price Wt Price
Cr £ s d Cr £ s d Cr £ s d
1
8:0 38
5:5:14
64
15:12:6
1/7/
10:11½
35
5:12:6
63 16:5:1/3/2
17
12:6
3/7/
6:0:17 62 16:18:0
18
15: 1½
4
6:8:0
65 17:11:13
11/12/2
18:0
4/
6:16:732
63 18.4.6
1/
1:1:1/3/2
44/
7:4:6
6% 18:18.13
13
7:4:6
4号
​7:13:13 7 19:12:0
17
1 : 8 : 1½
42/3/2
8:2:0 7½
20:6:1½
2
1:12:0
45/55
8:11:11/2
7/3/4/
27:0.6
2备
​1:16:7½
43
9.0:6
7/3/
27:15:13/
24
2:0:6
4 / /
9:10:7/3/
7/1/2
22:10:0
23
2:5:74/
5
10:0:0
750 23:5:73
23
2:10:0
5/17/
10:10:13/
73 24:0:6
2 1/1/00 2:15:1
5/1/
11:0:6
7/%/ 24:76:73
23/03
3:0:6
54
17:71 72
8 25:72:0
2급
​3:6:1/7/2
5/1/
12:2:0
81
26:8:12
3
3:12:0
5/15
12:13:12
8/4/274:6
37
3:18:17
53233
13:4:6
8-32353
28:1:1/2/2
34
4:4:6
5%/%
13.16 1/2
8/3/ 28:18:0
33 4:17:172/2
6
14:8:0
84
29:15:7/2/2
37
4:18.0
6 ž
15:0732
87 30:12.6
26

Large Pearl continued.
Wt Price Wt Price Wt Price
Cr £ s d Cr £ s d Cr £ s d
877 31:10:13/
77/31/2 52:18:0
74ㅎ ​79.76·732
9
32:8:0
1150500
54:1: 1½
74
87:4:6
9
33.6·1/½2
773/
55:4:6
143
82:13:1½
94 344:6 11/4/
56:8:13½
7412
84:2:0
93 35:3:7/½/2 72
57:12:0 145
85:11:1½
9/32 36:2:0
123
58:16:12 || 142
87:0:6.
9
37:7:7½ 123
60:0:6 747
88:10:12
9
38:0:6
72
67:5:7½
15
90:0:0
9739:0:172
12호
​62:10:0
15/%/
97:10:132
10
40:0:0
12€
63.15:1½
75元
​93:0:6
10% 47:0:72
12号
​65:0:6
15%
94:11:1/2
10% 42:0:6 12급
​66:6:132
153
96:2:0
10%/
43.711 13
67:72:0
15/5/
97:13:13½2
10½ 44:2:0 133
68:18:17½
153 / 99.4.6
10 45:3:13½-½
13/14 70:4:6
15% | 100:16:13½/
10% 464·6
133 | 71 11: 1½
16
102 8:0
10% 47:6:732
13 ½
72.78: 0
16%
104·0:1½
17
48:8:0
13 -/-/-/
74:5:1½
16
105:12:6
11% | 49:10:12
132
75:12:6
763 | 107:5:1½
17
50:12:6
137
77:0:7/7/2
16½ 108:18:0
113 57:15:13 14 78:8:0
16/5/ 110:11:12
27

16%
16385
173.78:7½ 10/2/2
17
115 12:0 19 154:1:12
Large Pearl continued:
Wr Price Nt Price W Price
Wt
Cr £ s d Cr £ s d Cr £ 3 d
712-46 19 750.3 : 7½
Z
|
752.2.0
s
193:12:0
22
22
221/195.76:7½2½
198.0:6
17/3/
174
17
777:6-7½ 103 156:0:6
119:0:6 193 158:0.1½
|
120:15:14 20 160.0:0
22% 200:5:17
222 202:10:0
22 204.15.13
77호
​722:10:0 20%
162.0.1½
22/3/
207:0:6
178
1245:7ź 20%
164:0:6
223200:6:1½
773
126:0:6 202
766:1:1/3/2
23 271:12:0
17%
127:16:13 2012
768:2:0
23/
273:18:12
78
129:12:0 205
170:3:12/
23/
216:4.6
186
131:8:1½ 20
172.4:6
23 218:11:1½
187
733:4:6 20/
174:6:13½/2
23
2
220:18:0
18.3 135:1:1/2 27 176:8:0
23
223:5:142
183 136:18:0 216 178:10:1/2/2 28
225:72:6
1985 138:15:12 214 180:12:6
23.
228:0:1/2
18/23/
140:12:6 || 21?
182:75:122
24
230:8:0
183 142:10:14 27½ 184:18:0
243
232:16:14/2
19
1448:0 27 187:1:142
198 146:6:19 213 189:4: 6
244
235:4:6
243 237:13:1½
19*
118.4.6 213 1977:8.12
24/2/1
240:2:0
28

Large Tearl continued.
Wt Price Nt Price Wt Price
Wt Wr
Cr £s d Cr £ s d Cr £ s d
24-1/ 242 71:12 29/1/ 348:2:0 34 483:0:6
24$ 245.0:6
29
354:0:6
35
400:0:0
243 247:70:73 30
360:0:0
35% 497·0:6
25
254
250:0:0
255:0·6 30½/2
30%
366:0:6
35% 504:2:0
372·2·0
35 577:4:6
25½ 260:2:0 30
378.4:6 36
578:8:0
}
26
25 2654.6 37
270:8:0
384:8:0 36 525:2·6
312
390:12:6 36 532:18:0
264 280:18:0
26 286.4.6
27 297:12:0
27 297:06
27½ 302.10:0 32 429:06
27 308.0:6
26 275.126 31½ 396:18:0 36 540:46
31/32/403·4.6
37
37 547:12:0
32 400:12:0 37 555:0:6
32% | 416:0·6 || 37½ 562:10:0
32 422:10:0 372 570:0:6
9
38
577:72:0
33 43.5.12.0 38% 585.4.6
28
313.12.0 33% 4424.6 382 592:18·0
287 379:4:6
333
287 324:18:0 33 45572.6
448:18:0
382 / 600.12.6
за
608:8:0
28 330:72.6 34 462:8:0
20
330:8:0 34% 469.4.6
20+ 342:4:6 34% 476.20
39% 6164.6
307 624:2:0
30 632.0.6
392-632:0:6
4

29
Large Pearl continued.
Wt
Wt Price Nt Price Nt Price
Cr £'s d Cr £ s d Cr £
40 640:0.0
45% 819:0:6
40% 648:0:6 45 828:2:0
402 656:2:0 45 8374·6
8
40% 6644:6 46 846:80
51 1040:8
513 1060:18
52
1087:12
523
1102 70
41
672·80 46% 855:12:6
53
1123:72
41 680.12.6 462 86418:0)
462864:18:0
53
1744 18
11½ 688.18.0.
4638744.6
54
1766:8
41 69746 47 883-12:0
54½
7788:2
42
42
705.72.0
7140.6 47½ 902.10.0
47% 893.0.6 55
7210:0
|
55
1232 2
42
423
722:10:0|| 473 912.0.6
731·0:6 48 927:72:0
43 730:72:0
56
56½ 1276·18
7254:8
48% 937.4.6
57 7299:72
431
7484.6
48½ | 040.18.0
57½ 1322.70
432 756:18:0 48% /
950:726
58 1345:12
43 765-126 || 49
|
960:8:0
58½
1368 18
44
7748·0 49
9704-6
59
1392·8
444
783.4 6
32
49 9802:0
59½ 1416:2
44+
792.2.0
49$ 990:0:6
60 1440:0
442
801:0:6
50 10000:0
60% | 1464 2
45
810:0:0 50% 1020:2:0
61
1488 : 8

30
Large Pearl continued.
Wt Price Wt Price Wt Price
Price|Wt
Nt Nt
Cr £ s Cr £ s
Cr £ s Cr £ s
67/1/2/
1512 · 18
72 2073:12
90
3240:0
62
7537:72
72/1/2 | 2702:10
623/2
63
1562:10 73 2731:12
1587:12 7371 2160:18
63½ 1612:18 74
2190:8
64
76388 74
2220: 2
64½ 1664:2 75
2250:0
65 7690:0
76
2310: 8
65½ | 1716 · 2
77
2377:72
66 1742:8
78
2433:72
དྱེ ཤྲི 8 བཻ 8 དྱེ ི ཙྪཾ ཅུ
3312:8
3385:12
93 3459 12
3534.8
3610:0
3686:8
97 3763 72
98 3841:12
99 3920·8
662 | 1768:18
79
2496:8 100 4000:0
67
7795:72 80
2560:0
67 1822:10 87
2624:8
68 7849:72 82
2689:12
68½ 1876:18 83
2755:12
6919048
84
2822: 8
692 1932:2 85
2890:0
70 1960:0 86
86
70½ 1988:2 87 3027:72
2958:8
77
2016:8 88 3097:12
71ź 2044:18|| 89
3768 8

UNIVERSITY OF MICHIGAN
3 9015 04920 6116