The Cambria freeman. [volume] (Ebensburg, Pa.) 1867-1938, 1893-01-27
IMITATION GEMS.
How Many Kinds of Precious
Stones Are Counterfeited-
Rock Crystal Plays an Important Part In
the Manufacture OF Artificial Jew
eIs-One Result OF Progress
In Chemistry.

THE finest imitation diamonds are
made out of rock crystal" p" said a Wash
ington dealer in precious stones To
Star man recently. THE basis of the
most successful counterfeits of all kinds
of gems il pure, very dense and highly
transparent sort of glass, which II
termed paste in the trade. For false
diamonds this glass is simply cut and
polished in facets, while for initiating
other stones, such as rubies, emeralds-
sapphires, etc, metallic oxides are
mixed with IL.
In manufacturing glass for such pur-
poses the processes employed have to
be conducted with the utmost nicely.
FoE making even the best mirrors, the
necessary silica il obtained from ordi-
nary white quartz, while common win
dow panes are produced from sea sand
To "A large extent; hut, in this case, rock
crystal is substituted, composing about
fifty per cent. of the ingredients of the
paste. To this must Toe added twenty
two per cent. of carbonate of soda and
due proportions of calcined boraN, salt
peter and red lead. All of these things
are reduced To the finest powder. mixed.
fused together by heat ia a cruclble and
cooled slowly
beauty of the plate depend upon the
care taken in these processes. Thus
made II is all ready To- bc cut up into
diamonds and prepared for market. 1t
may be. however, that the manufac-
turer desires 10 produce counterfeit
gems of other sorts. II 50, he has the
means readily al hand Supposing that
he wants rubies, he fuses with paste
small quantity of peroxide of manganese
and IA trace of Cassius purple. which
will give the proper color. For cmer-
AIDS. he employs in like manner oxide
# iron and for sapphires oxide of CO.
bait
Topaz is easily formed in the cruel
Ulc by IniXin,: with one thousand parts
of paste forty parts of glass of anti
mOny and one part of Cassius purple.
FIR manufacturing other kinds of gems
there are methods equally simple. OF
course, none of these imitation precious
stones has the chemical constitution,
hardness. specific gravity or optical prop
critics of real ones. Accordingly their
falseness is readily perceived by an eX-
pert InaSnuch as the clements of
which various gems are composed are
well known, synthetic chemistry has
attempted To reproduce them by putting
the ingredients together and effecting
,.rystalliZatiOn in the laboratory. In
this way large masses of what might be
termed true ruby and sapphire are
turned out artIficially. such gem-like
material having some usefulness for in
dustrial purposes. although lacking the
brilliancy 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 attention
70 taking things apart are beginning 70
learn how II put them together. All
the gems are very simple in compost
tion and the problem is merely To maze
their elements crystalline properly. In
all such knowledge science has made
but little progress as yet. We do not
even know for what reason one sub
stance is transpal mt while an Dther Is
Opaque; though presumably there is
some relation between the arrangement
of the molecules in the transparent
body and the length of the light waves,
which, in the of the transparent
body, permits the latter To pass
through