Shepherdstown register. [volume] (Shepherdstown, Va. [W. Va.]) 1849-1955, 1901-08-08
Testing Precious Stones.

Genuine diamonds are generally rec
ognized at first glance by the JeWeier
with the naked eye and surely with
the aid of the masnifying glass. An
imitation never exhibits as vivid re-
fraction besides, it is usually colorea
on the underside and foliated, which
is supposed to equalize the deficiency
The greater refraction is also perceptl-
BILE when the genuine diamond "
placed under water together with the
imitation. The latter is extinguisbed
to iuvisibility, while the genuine stone
sparkles even under water and is DIS
tinctly visible. If the diamond be
passed over piece of window glass;
it will penetrate without use of force
and the glass may be broken BY very
slight pressure. A false stone scratch
es the glass but specifically.
If drop of water be placed BY
means of a needle on the stone to be
tested which has previously been thor
oughly cleaned, the drop will de-
liouesce on an imitation, while it re-
tains its drop shape on true diamond.
A strip of aluminium may be passed
over diamond from which all grease
has been removed without it acquiring
even trace oft. On limitations, how
ever, the metal will give off some Of
its color.
A sure medium is also fuOhydrlc
acid, which is kept in c.outchOuc bot
ties, since it eats into glass and all
silicious compounds, including false d.
almonds, and frosts them, while the
genuine diamond issues unscathed
from the test, retaining its full bril-
liancy. If one makes an ink spot on
white paper and views it through the
stone, a counterfeit can be recognized
by the fact that the spot appears
multiplied (double) and with indis-
tinct outlines If necessary, mag
nifying glass may be called into re-
QUESTION. If the stone to be tested
is slowly drawn over a piece Of red
or white cloth while looking at 1t
through the magnifying glass, the col
ors will not be visible if the stone be
genuine.
A spurious diamond is usually cut
much more regularly than a genuine
one, for in the latter a certain limit ia
reserved, so as TO spare the valuable
material as far as possible, while in
the worthless material Of the imitation
there i, nothing to be saved. There
fore a striking regularity Of the cut
is suspicious sign.
Very well known is the test for
hardness. If the stone resists strong
attacks, it is certain to be genuine
fit can be ruined with steel file,
the damage is insignificant, as only an
imitation has been destroyed. This
test, however, does not hold good in
the case of other stones. 1t is true a
ruby which can be affected by steel
file or by quartz is suspicious, but the
emerald is scarcely harder than quartz,
and such test with topaz is liable
to injure a valuable stone
For examining rubies ard emeralds
the optical test is best. A glass mag
nifying about 100 diameters sufices.
Every expert knows that almost all
precious stones have little flaws
Nearly every ruby and all emeralds
have many defects, which are so
characteristic that the genuineness Of
the stone is readily established. Such
a test is very necessary with rubies,
because limitations are quite deceiviDg,
their color being absolutely durable
and often much finer than that Of the
genuine, although it may be stated
that somewhat yellowish cast is al
ways suspicious.
The only reliable way in which gen.
uine rubies can be told from limitations
is by the minute air bubbles Of the
latter which become clearly visible
under the magnifying glass. These
are not to be sound in the natural
gem. On the other hand the limitations
lack certain defects characteristic Of
genuinerub!es, certain vaccums whose
outlines are much more indistinct
than those Of the air bubbles of the
limitations.
Emeralds are always afflicted with
Characteristic defects, which, however,