The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1895-11-25

precious gems. Unless consignments
are so marked, the sales are consid-
cred fraudulent and are punishable
under the penal code. All sales effect
ed, amounting to some six or eight
hundred thousand francs, We're can
celed. and the money and stones re-
turned to their respective owners.
The action taken by the syndicate
clearly defined the position which this
production Will take among gem deal
ers, and there is little reason to fear
that the ruby will lose the place that
II has occupied for so many centuries.
Within a year quite number of these
stones have been placed on the Ameri-
can market as genuine.
NJ. NJ. HauteVille and Percy have
succeeded in making artificial emer-
aids by fusing silica, alumina and glu-
Gina with traces of oxide of chromium
with acid moly7bate of lithis heated to
six or seven hundred degrees for fifteen
days. Crystals were obtained having
all the properties of the natural emer-
aid, but scarcely thicker than a PIN
head
Carborundum and It's Utility.
One of the most interesting and use
full of artificial stones. and one of the
most remarkable products of modern
times. is carborundum. recently dis
covered by E. c. Acheson, who made
his first experiment in the laboratory
of Thomas A. Edison at Menlo Park,
New Jersey. 1t is essentially a carbide
of silicon, containing 6910 per cent. of
silica and 1920 per cent. carbon, and
is harder than all known substances
except the diamond. Its Industrial
value as an abrasive can scarcely be
overestimated. 1t is already largely used
in place of emery wheels in grinding
md ic1,i
diamonds. Extensive works are now
located at Pittsburg; but these already
proving inadequate, a 10000 horse
power plant will be erected at the New
Cataract company works, Niagara
Falls 1t is claimed that carborundum
can be used for polishing diamonds;
but my own experiments with it have
shown that. although it would scratch
ruby, sapphire, and white, yellow and
purple corundum, it would not scratch
the diamond, but was readily scratch
ed by a diamond; and also that on the
polishing wheels it did not abrade or
polish the diamond in the slightest.
The Vanities of Imitation Gems.
Imitation gems comprise first, what
are known as doublets. in which the
upper part of the gem is made of gar
net, quartz, or other hard stone, below
of the stone to be initiated.
Second, those made entirely of glass;
Of a very hard and brilliant kind
known as paste, colored with small
amounts of metallic oxides of the tint
desired.
Third, those which are made by heat
ing rock crystal and plunging it in a
solution the color Of the gem to be imi-
tated.
Sometimes both top and back are of
glass, while thin slab of the genuine
stone of inferior quality is inserted at
the girdle, SO that should the jeweler
try the hardness at that point Gotten
the only exposed place that can be
tested) he is apt to be misled. These
are called triplets.
All imitation gems except the last
group, consist of the hard glass called
strass or paste. This paste is colored
with various metallic oxides, which inn
part certain tints. as cobalt for blue,
magnese of violet, and nickel, copper,
iron, chromium, ETC., for the other hues.
When uncolored, it is made into imi-
tation diamonds.
Sure Mark of Imitation in Gems.
The one point in which all such imi-
tations fail, is hardness. Practically
they all yield to the quartz and the
file, and many are scratched even by
q bit of glass
Besides their softness, they tarnish
in impure air, the lead becoming
brown; and they are heavier than any
of the stones they represent Under
the microscope, or even a hand magni-
fer, most of them show fusion lines,
specks, and bubbles which betray their
origin and nature. The lines and striae
are signs of layers of unequal density
and strain. The bubbles are rounded
or pear-shaped cavities, quite different
from the cavities with angular and
crystalline walls, which some gem
stones, such as amethyst, beryl and
topaz frequently present. This latter
test is also conclusive with reference
to the fused compounds or artificial
gems from the chemists laboratory.
Imitation diamonds, unlike the arti-
fetal, are very common. We often
hear of 'diamond-coated" stones, Lake
George, California, Sphinx, South At
rican, Partisan, Rhine-stoneS, French
paste, and other limitations. They are
all of the same substance paste or
lead-glass, as above described. 1t has
much more play of color, or fire, than
rock crystal or almost any other white
stone except the diamond, but it has
less hardness than any of them, even
less than window-glass, and though
showing fire, is devoid of lustre. OF
late years these limitations have been
much improved in brilliancy by hav-
ing the backs silvered like a mirror,
or fitted with small metal caps filled
with mercury, whence they are called
foil-backs. Attempts to improve their
hardness, however, have only resulted
in a loss of brilliancy. The best of
them can be imported by the gross for
% cents apiece, or even less; yet they
are often sold by the carat to lend inn
pressiveness to the transaction.
The Traffic i'm Imitation Gems.
The greater the sale of limitations,
the greater the sale of genuine stones,
as our import lists will show. Some
times jewels which have been kept I'M
used in their cases for some years,
when. finally taken to the jeweler to
be cleaned or repaired are found to
be wholly or in part glass. Among
many instances may be mentioned a
ring of Daniel Webster's set with nine
diamonds, two of which were recently
found to be limitations.
The first mention of the sale of any
considerable quantity of imitation dia-
monds was at the end of the last CEN