Evening star., 1902-08-21
TESTS OF DIAMONDS.
Simple but Scientific Ways of Judging
Gems.
From the London Express

From the London Express
ANY one can tell a genuine diamond or
precious stone even from a very clever imi-
taton There are few household tests
winch are practically infallibIe The dia-
mona expert, after long years of experience
with gems, can detect an imitation, as a
rule at glance. The layman in such mat
ters' with few simple tests, takes more
tlme TO solve such problems, but his Judg-
ment IN the end Is scarcely less accurate
An limitation diamond is never SO bril-
llant as a genuine stone. If your eve is
not experienced enough to detect the diff
ference very simple test Is to place the
stone under water. The imitation stone is
practically extingushed, while a genuine
diamond sparkles even under water. and is
distinctly visible. When possible place a.
genuine stone beside the possible imitation
under water and the contrast will be ap-
parent to the least experienced eyes.
The glass-cutting test is, of course. more
OF less familiar. 1t is probably the most
common raise diamonds are usually cut
more regularly than the genuine stones In
cutting a diamond the material is saved as
far as possible. In any imitation the ma
ter1al is Itself worthless, and no attention
is made to suit the size or angle of the
facets to the form of the stone. 1t can
be put down as a safe rule that when a
stone is cut with great evenness and regu-
larity 1t Is, to say the least, a very sus-
picfous sign.
Another very simple and effective test is
to place drop Of water on the stone and
carefully observe the result The stone
should first be carefully cleaned. On an
imitation diamond the drop, however small,
Will deliquesce. The drop will, however
retain its original shape on a true stone
10 make the test quite sure use a magnify
ing glass when watching the action of the
drop.
Still another test of this nature is to pass
the stone over piece Of aluminium Both
the metal and the stone should be abso-
lutely free from any trace of grease The
metal will give off some of Its color to an
imitation stone. while genuine diamond
Will remain perfectly clear and unaffected
Among jewelers. the final test is to apply
drop of f1uorhydric acid to the stone un-
der suspicion. The acid will eat into any
false diamond and frost it, while the genu-
inc stones will not be damaged In the
slightest degree.
Perhaps the simplest method of all, how
ever, is to examine an ink spot on a sheet
of white paper through a diamond, by hold
ing the upper surface against the eye. If
the stone be counterfeit the black spot will
appear greatly multiplied. or at least
doubled. The outline will, moreover, appear
blurred and indistinct. BY using magni-
flying glass the test can readily be made
absolute.
The optical test is the best in examining
rubes and emeralds. 1t is commonly sup
posed that such stones can be best test ted
by rubbing them with file, that the gen.
uine stones resist the steel, while the imi-
tations only will suffer; but the test is not
exhaustive. The best plan is to examine
them closely with microscope of about
100 diameters. The genuine stones have
number of minute flaws, whereas the imi-
tations are likely to be much more nearly
perfect in texture.