diamonds
are known which give out light from the cubic faces but not from the
octahedral, while others are reported as giving out light of different
colors from different faces.
The name diamond comes from the Greek adamas, which
means unconquerable. This term was doubtless applied because of the
great resistant power assigned to the mineral by the ancients. Besides
the well-known tradition that it could not be broken by hammer and
anvil, they believed that the diamond could be subdued or broken down
only when dipped in warm goat's blood. Our words adamant and adamantine
are also derived from adamas, the latter term still being used to describe the luster of the diamond. The change of adamas into the word diamond is thought by some to have come from prefixing to it the Italian diqfano, transparent, in allusion to its possessing the property of transparency.
According
to classical mythology the diamond was first formed by Jupiter, who
turned into stone a man known as Diamond of Crete, for refusing to
forget him after he had ordered all men to do so. Many medicinal
virtues were ascribed to the diamond, it being regarded as an antidote
for poisons and a preventive of mania.
The
world's supply of diamonds has come almost wholly from three countries
— India, Brazil, and South Africa. Up to the beginning of the
eighteenth century India was the only source of diamonds known. The
diamond fields of India occur chiefly in the eastern and southern
portions of the peninsula. The famed region of Golconda is in the
southern part. This is the territory whence have come the most
celebrated Indian stones, such as the Kohinoor and the Hope Blue. The
French traveler Tavernier reported when he was there in 1665, that
sixty thousand men were then employed in these mines. Now the mines
have all been given up and the region is abandoned.
The
present yield of Indian diamonds comes almost wholly from mines in a
district south of Allahabad and Benares. The diamonds occur here, as
universally in India, in a conglomerate or sandstone made up of the
remains of older rocks.
The
mines are worked almost wholly by natives of the lower caste, attempts
of Europeans to conduct the mining not having met with success. The
natives separate the diamonds by washing, or where the rock is too hard
for such methods, break it up by heating and throwing cold water upon
it. The production of diamonds from all of India is at the present time
very small, not reaching a million dollars a year in value. It is
likely in time to disappear altogether, since most of the old mines
have been abandoned, and even their location forgotten, and the returns
from the present mines are not very profitable.
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