Evening star. [volume] (Washington, D.C.) 1854-1972, 1912-04-21

size, the largest of the synthetic diamonds
being only about one millimeter in diameter
yet it is diamond.
Moisson first produced minute diamonds
in the electric furnace. Everyone knows
how salt will dissolve in water, and in an
analogous manner carbon, in the form of
charcoal, will readily dissolve in large guam
titles in molten iron. Under ordinary con-
ditions of cooling mass of melted iron con-
tanning carbon dissolved in it, the carbon
will slowly separate as black graphite like
the material of our pencil points.
Moisson reasoned that if he was able to
modify the conditions of cooling so as to
deposit the carbon in crystalline form, he
would have diamond instead of graphite.
To accomplish this, he first prepared some
pure carbon from sugar, and forced this by
means of high pressure into a cylinder of
soft iron. This cylinder containing the car
bon was then plunged into mass of molten
iron in the electric furnace. The carbon dis
solves in the iron. Then this mass of metal,
at temperature of twenty-five hundred de-
grees Centigrade, is suddenly plunged into
ice water. The metal thus quickly cooled
contracts on solidifying, and the outer layer
clamps the inner melted mass, thus exerting
terrific pressure on the carbon, which is at
ditions the crystalline modification of car
bon, diamond, is formed.
The element of carbon of which diamond
is composed is peculiar in the fact that its
boiling point of thirty-f hundred degrees
Centigrade is below its melting point. TAX
ing these facts as a basis, Sir William
Crookes reasoned that in the making of
synthetic diamonds temperature of forty
two hundred degrees Centigrade and pres
sure of two hundred and fifty-6ve pounds
should be employed. During some expert
ments with the terrific explosive, cordite,
which were carried out in closed vessels by
Nobel, temperature of ffty-two hundred
degrees Centigrade was reached, and after
ward Sir William Crookes found microscopic
diamonds in the explosion chamber.
So the day may not be far off when it will
be possible to manufacture synthetically
from the ugly commonplace SCOT of our
chimneys, diamonds large enough for use in
jewelry.
Not only have the ruby and the diamond
been synthesized, but other gems as well.
Ebelman has made beautiful specimens of
spinel and chrysoberyl from oxids of alumni
mum and beryllium in solvent of boric
oxid. Topaz is complex f1uor silicate, and
it can now be made by the action of f1uorides
of silicon on oxids of aluminium. Recently
Petereit made sapphires large enough to be
cut into small gems, identical with the ma
tive stone in all of its properties.
Part Imitation. Part Genuine
RESIDES the making of synthetic and
artificial stones, there is still another
division in the fabrication of gems. Some
stones offered for sale are part imitation,
with genuine crowns. The body or base is
paste, while the crown is genuine, and they
are SO cleverly made together that without
closest scrutiny it is impossible to detect the
fraud. When such stone is placed in ether,
alcohol, or carbon bisulphid, the cementing
materials between the two parts are dissolved
and they separate.
There is also clever process for the manu-
facture of imitation pearls. These consist of
hollow glass beads coated on the inside with
fsh-scale preparation. 1t is clever i'm
itation.
Last of all, stones are now made from the
chips and powder formed in the polishings
and cuttings of the lapidary. These scraps
are fused together in the electric furnace and
make good grade of medium priced jew
elry.
The jeweler, lapidary, or dealer in pre-
cious stones is often called on to decide
whether a stone is genuine, synthetic, or
artificial. 1t is an easy matter to distinguish
between natural and artificial gems; but it
is next to impossible to say whether a ruby,
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