Morning journal and courier., 1894-05-22
DoCTORING DIAMONDS.
Clever Ways in which Precious
stones are Faisiusd te Increase
Their Apparent Value.


Stones are FaIxined 10 Increase
Their Apparent Value.
Prom the London Pail Mall GaEeite-l
The practice of fAlsifying precious
stones, especially diamonds, in order to
make them appear to the inexpert more
valuable, is not by any means modern. 1t
can be traced back to the fifteenth century
and to Holland, where diamond cutting
and setting had its rise as sn art. With
the growth of the trade in diamonds and
other precious stones, various illegitimste
means were devised of imposing upon the
purchasing public, and enhancing the sp-
parent value Of gems offered for sale.
Some of these practices date back hun
dreds OF years; others belong to a modern
period, and are almost co-inoident with
comparatively recent discoveries in chemi-
cal science.
By dealers and the trade generally dia-
monds are separated into various classes,
and known by special names. These
terms relate mainly TO the method In which
Q gem Ia cut. Diamonds cut to q point,
with more or less fscsts, sre called bril-
lisnts; those presenting fiat surface are
known as table stones. The term brilliant
is properly applied only to q stone cut In q
certain form; but IN the practice of the
trade IL is given elso TO colorless sspphires,
rubies, emerslds, Oriental topszss, and
few other gems. All such stones, whether
quite colorless, or with areenish, yellow
ish or blush tint, are of nearly equal
value. provided they reach q given stand
ard of hardness. In the trade diamonds
from India, Brazil or Africa are generally
clsssed together The name "Orientsl d.
smond" does not denote that the stone Is
of eastern origin, but that 1t is of superi-
OF quality. Gems spoken of as "Rio" di-
almonds msy or may not have been mined
In the Brszlls, the name only s'gnifyipg
that they are of second quality; while
"Cape brillisnts" include all less valuable
stones. Formerly spurious diamonds were
mostly formed from rock crystals. Many
of the 80 called diamonds found In antique
snuff boxes, watches and miniature frames
ara in wealthy rockSsrystsl ir'.ta.ioan Of
real gems-
The value of diamonds and other gems
depending mainly upon their bulk, the sf-
forts of fslsifiers have been chiefly direct
ed to increasing the proportions. The
principal mode of 80 doing lie known as
doubling" It was in use in the seven
teenth century, and q case lately before
the law courts In references to a so-cslled
ruby shows that 1t is still hourisbing. 1t
consists In joining together with cement O
| portion of O real stone and an imitation 60
| as to make the combination sppesr one
and indivisibls. This can be done SO deft-
ly that the initiated are sometimes de-
ceived, as the case referred to above gocs
| to show. So long ss a combination of this
kind remains unset the expert discovers 1t
usually by close examination Of the
| edges; when 1t is mounted in ring, brace
II La otha 10 l.
| cslly impossible. This is the most COM
| mon form of deceit Ia the jewel trade. If
l some of the jewels priced by noble and
L priucely houses were taken to pieces and
| carefully examined by an expert the re
i suit might sstsnish the owners Some
surprising discoveries of this kind have
been made when family jewels were being
remounted.
1t is to guard sgainst deceptions of this
| kind that jewellers and dealers in precious
stones decline to buy gems In their Get
tipgs. When the gem is unset 1t can be
easily sub jected to a ready and infsllible
test. A stone about which there may be
suspicion is dropped into dish of very
hot water II IL Is "doublst" the ce-
ment quickly dissolves, and the compo-
nent parts fall ssunder. But "doublets"
are also made In which the real diamond
finds no place. The art of glsss msnutac
/ ture has made many snFsnces III EeCeua
yesrs, and experience has taught those
who make Il their business to fsbricate
/ spurious gems that q better result and q
| closer initiation of the genuine article can
be obtained by joining two pieces OF elsss
/ of diverss shades. 1t lie managed In this
wsy. The top portion of the false bril-
liant is made from glass In which there lie
| q pale yellow or straw coiored tipge. In
the under side Of this socket is drilled;
into this socket Is fitted stem of glass of
a lipht bluish shade, the result Of the COM
binstion being that the false stone CLEANS
and spsrkles like a gem of the pures,
/ water. The best limitations Of this de.
| scription are go effective that when well
| mounted they deceive all but the finest
judges.
Among the tests used by dealers and
jewellers to ascertain not only the reality
but the quality of diamonds offered for
sale Ia that Of resistance or hardness
Few professionals are without q case oi
proved diamonds, graded according tc
their degree of hardness All purchases
| are tested by this scale and their quality
/. ascsrtsined- A specially constructed mi
| croscope is need to distinguish colors IL
stones. 1t has been stated that diamonds
are seldom bought by the traae after they
are mounted. They are generally taker
out Of the setting for inspection. This u
more especially the case If the stones ar,