The free press. (Poplarville, Miss.) 1890-19??, 1892-08-04
GEMS MADE BY ART.
How Counterfeits Of Precious
Stones Are Manufactured.
Chemists May in Time Provide
Gems by Artificial Means.


"The finest imitation diamonds are |
made out of rock crystal" said a
Washington dealer in precious stones
to writer for the Washington Star.
'Ilc bases Of the most successful |
ceuntcrfcits of all kinds of gems Is u
pure, very dense and highly trans
parent sort of glass, which is termed
paste in the trade, For diamonds
this glass is simply cut and polished
i'll facets, while for initiating other
stones, such as rubies, emcralds. sap
phires, &C., metallic oxides are mixed
with it.
'In manufacturing glass for such
purposes the processes employed have
to be conducted with the utmost
nicely. For making even the best
mirrors the necessary silica is obtained
from ordinary white quartz, while
common window panes are produced
from sea sand to u largo extent, but
in this case rock crystal is substituted,
composing about so per cent. Of the
ingredients of the paste. To it must
be added % per cent. of carbonate of
soda, and due proportions Of calcincd
boraX, saltpetre and red lead. All of
these things arc reduced TO the finest
powder, mixed, fused together by
heat in crucible and cooled slowly.
"The density, Transparency and
beauty of the paste depend upon the
care taken in these processes. Thus
made it is all ready to be cut up into
diamonds and prepared for market.
1t may be. however, that the manu-
facturer desires to produce counterfeit
gems of other sorts. If so, he has
the means readily at hand. Supposing
that he wants rubies, he fuses with
the paste a very small quantity of per-
oxide of manganese and trace of
Cassius purple, which will give the
proper color. For emeralds he tm-
ploys in like manner oxide of iron,
and for sapphires oxide of cobalt.
"Topaz is easily formed in the cru
chile by mixing with 1000 parts of the
paste 40 parts of glass of antimony
and one part of Cassius purple. For
manufacturing other kinds of gems
there are methods equally simple. OF
course none of these imitation
precious stones has the chemical con-
stitution, hardness, specific gravity or
optical properties of real ones. Ac-
cordingly their faIsencss is readily
perceived by an expert. lnasmuch as
the elements of which various gems
are composed are well known, SYN
thetic chemistry has attempted to re-
produce them by putting the i'll
sfodients together and effecting crys-
tallization in the laboratory. In this
way large masses of what might be
termed true ruby and sapphire arc
turned out artificially, such gem-likc
material having some usefulness for
industrial purposes, although lacking
the briliancy of natures products.
"For my own part ] am confident
that sooner or later some, if not all, of
the stones deemed precious will be re-
produced by artifice. The chemists
who have hitherto confined their at
tention to taking things apart are be-
ginning to learn how to put them to-
gclhcr. All the gems are very simple
in their composition, and the problem
is merely to make their elements
crystalize properly. In all such
knowledge science has made little
progress as yet. We do not even
know for what reason one substance
is transparent while another is Opaque,
though presumably there is some rela-
ton between the arrangement of the
molecules in the transparent body and
the length of the light waves, which,
in the case of the transparent body,
permits the latter to pass through"