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THE RUBY
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has
no cleavage. It is found in China, India, Burma, Ceylon, South Africa,
America, and in many other places, having a wide distribution.
The Ruby.
In
the dichroscope the ruby shows two images, one square of a violet red,
the second square being a truer and a paler red. It may be subjected to
strong heat, when it changes its colour' to a sooty or dirty slate,
this varying with the locality in which the stone is found, and the
manner in which the heat is applied. But as it cools it becomes paler
and greener, till it slowly enrichens ; the green first becomes broken,
then warmer, redder, and finally assumes its original beautiful blood
red. This method of heating is sometimes used as a test, but it is a
test which often means the complete ruin of a stone which is not
genuine. Another characteristic which, in the eyes of the expert,
invariably isolates a real from an artificial ruby is its curious mild
brilliance, which as yet has not been reproduced by any scientific
method in paste or any other material, but perhaps the safest test of
all is the crystalline structure, which identical structure appears in
no other stone, though it is possible, by heating alumina coloured
with oxide of iron and perhaps also a trace of oxide of chromium to a
very high temperature for a considerable time, and then cooling very
slowly, to obtain a ruby which is nearly the same in its structure as
the real gem ; its specific gravity and hardness may perhaps be to
standard, and when properly cut, its brilliance would deceive all but
an expert. And as in some real
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