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Birthstone For July: Ruby
The July birthstone is the "Gem of Gems", the ruby, which is a variety of
corundum, a transparent gemstone, the crystalized form of the mineral
alumina. Its color varies from a medium red to a "blood red" which sometimes
has a purplish tint. The color is due to the presence of a small amount of
chromium. The hardness on Mohs scale is 9, and is next to that of the
diamond. This gem has been prized for centuries in the Orient, and the
location of the mines were long a well-kept secret. A form occurs as
"star" stones, which are very rare, expensive, and attractive. The major
sources of the quality gems are Burma and bordering China, Siam, Ceylon
and India. Some fine specimens have been found in Montana and in North
Carolina.
-- by Axel E. Janson
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