94 A Book of Precious Stones
sapphires
present the same six-rayed gleams of light that are sometimes
manifested by the ruby, but they are usually much more marked in the
sapphire. Sometimes a sapphire presents but an irregular patch of
opalescent light, when it is called "sapphire cat's-eye" or " Oriental
gi-rasol." Star-stones are never transparent throughout, and their
cloudiness, due to enÂclosures of minute tabular crystals, or
tiny tubular cavities, the latter in sets, is believed to cause the
star-rays; the exact manner has been variously explained but not
scientifically demonstrated. Star-sapphires are cut en cabo-chon. Sapphires being more common than rubies are less valuable.
Sapphires
are found in about the same minÂeral situations as rubies,
predominating in some localities as rubies do in others. They are more
abundant than rubies in Siam, although they are mined in different
localities. They are found in Ceylon, in Kashmir, in the north-west
Himalaya Mountains, in the gem-gravels of Australia, and in Montana in
the United States. Siam produces most of the sapphires marketed and
those of the best quality. Mines at Bo Pie Ein in Battambang, Siam,
yield five-eighths of the world's sapphire product. The sapphire
