Chicago eagle. [volume] (Chicago, Ill.) 1889-19??, 1894-12-01
FALSE DIAMONDS.
PaAcTicco 70 IN.
CREASE THEIR VALUE,

Swelling Their Size by "0eubIins"..
Altering che Shade % q Stone.
Spurious Gems.
The value OF diamonds and other
gems depending mainly upon their
bulk, the efforts of the !olsifiers have
been chiefly directed 10 increasing
the proportions, sayi the Pail Mall
Gazette. The principal mode of SO
doing is known as doubling" II
was In use in the seventeenth cen.
fury, and n case before the law courts
In reference to u so.colled rule showA
that IL Is still nourishing. 1t consists
in joining together with cement q
portion Of a real stone and an imita.
ton SO rs to make the combination
appear one and indivisible. This can
be done so deftly that the initiated
are sometimes deceived, as the case
above referred to goes to show.
So long as combination Of this
kind remains unset the expert dis
covers It usually by a close examine
ton of the edges; when 1t Is mounted
in u ring. bracelet or other setting
recognition is practically impossible.
This Is tho most common form OF dc.
ceit in the jewel trade. II some 81
the jewels priced by noble aud
princely houses were taken to pieces
and carefully examined by an expert
the result might astonish the owne.'s.
Some surprising discoveries Of tbs
kind have been made when family
jewels were being remounted.
It is to guard against receptions OF
this kind that jewellers and dealers In
precious stones decline to buy gems
in their settings. Wien the gem Is
unset it can easily be subjected to "a
ready and intallible test. A stone
about which there may be suspicion
is dropped into dish OF very hot
water. II It is n "doublet" the
cement quickly dissolves. and the
component parts fall osunder. But
"doublets" IRE also made in which
real diamonds find no place.
The art of glass manufacture has
made many advances In recent years,
md experience has taught those who
make 1t their business to fabricate
spurious gems that better result
and u closer imitation Of the genuine
article can be obtained by joining two
pieces Of glass Of diverse shades. 1t
Is managed In this way: The top
portion of the false brilliant is made
from glass In which there Is n pale
yellow or straw colored tingc. In the
underside of this u socket Is drilled,
into this socket Is fitted stem oil
glass of light blush shade, the re-.
suit OF the combination being that
the false stone CLEANS ind sparkles
like gem Of the purest water. The
best limitations OF this description
IRE so effective that when well noun.
ted they deceive all but the best
judges.
Among the tests used by dealers
and jewellers to ascertain not only the
reality, but the quality Of diamonds
offered for sale Is that OF resistance
or hardness. Few professionals are
without case OF proved diamonds,
graded according to their degree Of
hardness. All purchases are tested
by this scale, and their quality ascer
tained. A specially constructed MI
croscopc Is used to distinguish color
In stones. 1t has also been statet
that diamonds are seldom bought by
the trade after they are mounted
They ure generally taken out Of tn,
setting for inspection. One Of the
oldest tricks OF the trade Is to sc
color tho bed In which the stone rests
as to change the hue OF the gem,
For instance, q ruby will glow with d
deeper and more intense fire II tho
bottom aud sidcs Of the settin Z
wherein II Is fixed be colored red.
Tho shade of u stone can be altered
or u flaw concealed by the skillfuI
use OF colors in this way. Naturally,
this device does not deceive the inl'
tiated. A perfect stone Is invariably
mounted ~ jour-" or SO that every
part Of 1t Is visible.
The discovery Of diamonds In South
Africa led Indirectly to some clever
deceit by the dealers. Many OF the
South African diamonds have n straw
tint. which has an unfavorable effect
on THOR price, especially as experts
believe that 1t will become more do
cided the longer tho stones are ex'
posed to the mir. Some OF the more
knowing dealers discovered that by
subjecting the straw-tinted diamond:
to bath Of certain acid.
the Objectionable color was re-
moved and the gems became
pure white, A number Of diamonds
So treated were sold in Paris and Ber
lin, and brought higher prices thar
II they had retained their origlna
color. After exposure to the air for 1
certain length Of time tho original
color returns, but by that time they
have passed out Of the dealers hands
Tho flald was soon found out by the
trade, and now they guard against
impositions of such u character by
means OF various tests. OF these, Tho
most generally used are the hot water
bath and friction. fla dyed stone b,
left in hot water for few minutes i
resumes its original hue; or II til,
gem be rubbed sharply on u towel
or even on u coat sleeve, its norma
color can be detected. These test,
are simple and chicacious, and il
daily use.
PopuIarity Of Scjencs,