The Black range., 1895-06-07
IMITATION GEMS.
How Many Kinds Of Precious
Stones Are CounterSeited.
Rock Crystal Plays an Important Part In
the Manufacture OF Artificial Jew-
els-One Result Of Progress
In Chemistry.

THE finest imitation diamonds are
made out of rock crystal, 4" said Wash
ingt0n dealer in precious stones TO a
star man recently. ''The basis of the
most successful counterfeitso Of all kinds
Of gems is a pure, very dense and highly
transparent sort Of glass, which is
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 Wi.A it.
I'm manufacturing glass for such pur-
poses the processes employed have to
be conducted with the utmost nicely.
For making even the best mirrors, the
necessary silica is obtained from ordi-
nary white quartz, while common win
dow panes are produced from sea sand
TO a large extent; but, in this case, rock
crystal is substituted. composing about
dfty per cent. OF the ingredients Of the
paste. To this must be added twenty
two per cent. Of carbonate Of soda and
due proportions OF calcined borax. salt
peter and red lead an of these things
are reduced to the finest powder, mixed.
fused together b. heat in a crucible and
cooled slowly.
tThe density, transparency and
beauty Of the plate depend upon the
care taken in these processes. Thus
made, it is al ready to be cut up into
diamonds and prepared for market. 1t
may be, however, that the manufac-
turer desires to produce counterfeit
gems Of other sorts. If so, he has the
means readily at hand Supposing that
be wants rubies, he fuses with paste a
small quantityof peroxide Of manganese
and trace Of Cassius purple, which
VIII give the proper color. For emer-
aids, he employs in ike manner oxide
81 iron and ior sapghires oxide of CO.
bait.
Topaz is easily formed in the cruel
ole by mixing with one thousand parts
Of paste forty parts of glass of anti
mony 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 constitution,
specific gravity or optical prop
critics Of real ones. Accordingly their
alseness IS readily perceived by an ex-
pert Inasnuch as the elements of
which various gems are composed are
well known, synthetic chemistry has
attempted to reproduce them byputting
.be Ingredients together and effectiDg
in the laboratory. In
This way large masses Of what might be
.ermed true ruby and sapphire are
.urned out art1fcially, such gem-like
having some usefulness for in
lustrial purposes, although lacking the
of natures products
For my own part, l am confident |
hat sooner or later some, if not all, of
ne stones deemed precious viii be re-
]roduced by artifce. The chemists who |
ave hitherto confined their attention
0 taking things apart are beginning to
aarn how to put them together. All |
l-e -1LLl' axe very slnAple IN COMPOST |
ion and the problem is merely to make |
heir clements crystalline properly. In |
Il such knowledge science has made
ut little progress as yet. We do not
ven know Tor what reason one sub
tance is transparent while another is
paque; though presumably there is
ONE relation between the arrangement
the molecules in the transparent
ody and the length of the light waves,
'hich, in the case of the transparent
ody, permits the latter to pass
lrough."