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PRECIOUS STONES 101
less
than a foot thick, lies between a coarse sand which forms the surface
of the country and the clay bed on which it rests. The mines are worked
by an English company which obtained a concession. The search for them
formerly was very irregular, owing to the claims and exactions of the
rulers.
Rubies
are found in similar deposits in the valleys and sands of rivers in the
island of Ceylon, principally in the neighborhood of Ratnapura and
Rakwena.
The Ameer of Afghanistan obtains rubies east of Kabul, and mines are worked at Gandamak.
Thibet yields some large specimens of ruby, but they are usually opaque and silky, cutting to star stones.
A few rubies have been found in Australia, but they are small and of little value.
Corundum
is found in North Carolina, and occasionally a ruby crystal of fine
color and quality is discovered. A gentleman connected with the
American Gem Company reported having met with some of exceptional
quality during a visit there in 1901.
The
color of the Burmah rubies excels all others, though some of a like
color are found in Siam. The rubies of Siam are usually dark, the red
being of a blackish shade. Those of Ceylon are a light rose-color or
pink. The red has a purplish tint, and as it degenerates is classed as
pink sapphire.
Barklyite is a magenta-colored corundum found in Victoria, Australia. It is almost opaque.
Whatever has been said of the nature and genesis of the ruby applies also to the sapphire.
The
sapphire is ordinarily blue of some shade to colorless. Usually it is
not a good night stone, the color becoming inconspicuous or black by
artificial light. Some sapphires appear reddish or purple and
occasionally violet by artificial light. The latter are rare and
valuable.
The color is supposed to be due to a small quantity of iron found in its composition, and is often very irregular.
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