Evening star. [volume] (Washington, D.C.) 1854-1972, 1892-06-04
GEMS MADE BY ART.
Commercials of Precious stones and Hou
They Are Manufacturer.

Counterfefte OF Precious stones and HOul
They Are ManufactureA.
ssrNHE FINEST IMITATION DIAMoNDs
Il are made out Of rock crystal" said :
Washington dealer in precious stones TO :
writer for The STAR. "The basis az the mos4
successful counterfeits OF all kinds Of gems il =
pure, very dense and highly transparent sort q
glass, which liz termed paste in the trade. fo}
false diamods this glass il simply cut aud poll
ished in facets, while for initiating other stones
such as rubies, emeralds, sapphires, &C., metal]
he oxides are mixed with Il.
In manufacturing glass for snch purpose}
the processes employed have 20 be conducted
with the utmost nicely. For making even thsl
best mirrors the necessary silica IL obtained
from ordinary white quartz, While common win-I
dow panes are produced from sea sand 20 q
large extent but in this rock crystal IL subj
stituted composing about 50 per cent OF the In !
gradients of the paste. To it must be added n
per cent Of carbonate OF soda. and due proper
tons Of calcined borax, saltpetre and red lead !
All of these things reduced 20 the fines
powder. mixed, fused together by heat in Z
crucible and cooled slowly
1.-The density, transparency and beauty OF the
paste depend upon the care taken In these pro-
cesses. Thus made il is all ready 20 be cut an
into diamonds and prepared for market Il
may be, however, that the manufacturer desires
70 produce counterfeit gems of other sorss
IL so he has the means readily at hand. sup
posing that he wants rubies. be fuses With the
paste a very small quantity Of peroxide II
manganese and a trace of Cassins purple. which
viii give the proper color. For emerslds he
employs In like manner oxide of iron. and for
sapphires oxide of cobalt.
Topaz Is easily formed in the crucible by
mixing with 900 parts Of the paste 20 parts OF
glass OF anthony and one part Of Csssius pur-
pie. For manufacturing other kinds of gems
there are methods equally simple. OF eours<
none of these limitation precious stones has th<
chemical constitution, hardness. specific grsy1
ity or optical properties Of real ones. Accord
ingly their falseness Is readily perceived by an
expert. Inasmuch ~ the elements Of which
various gems are composed well known.
synthetic chemistry has attempted 10 Reproduced
them by putting the ingredients together and
efecting capitalization IN the laboratory. Id
this way large masses Of what might be termed
true ruby and sapphire are turned out srti
hcially, such gem-like material having som<
usefulness for industrial purposes. although
lacking the brilIianey az nature q products.
For my own part, am confident that soones
or later some, If not all, Of the stones deemed
precious viii be reproduced by artifoe. Tho
chemists who have hitherto confined their at
tention 70 taking things apart are beginning u
learn how to put them together. All the gem
are very simple In their composition and ths
problem e merely TO make their elements crys
taIlize properly. In ali such knowiedge science
has made little progress a. yet. We do not ewes
know for what reason one SUBSTANCES II trans
parent while another rs opaque. though presum-
ment Of The molecules i'm the transparent body
and the length Of tbe light waves, which, in ne
10 pass through"