MINERALS

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again there must always be large opportunities for diamond
 stealing, and it is impossible to rival native methods
for preventing this constant source of loss. Also the
unhealthiness of the districts in which diamonds are
chiefly found is in itself fatal to much European enterprise.
 There is no part of India (possibly no tract in the
world) more fever-ridden and unwholesome than the
Godavari basin.
Yet it cannot be supposed either that the original
sources are exhausted, or that the field for enterprise
has greatly narrowed. There must be vast areas untapped
 as yet lying beneath the Vindhyan rocks of
the Central Province. The most celebrated diamond of
[ndia is the Koh-i-Nur, now a British possession. This
was apparently (for there are many histories attached to
it, and they do not by any means agree) found on the
Kistna River at Kolar, to the north-west of Masulipatam,
and is probably identical with the Great Moghul diamond
which was shown to Tavernier by the Emperor Aurangzebe
 in 1665. He describes the Kollur (or Kolar) mine
as being about 100 years old, and records that 60,000
people were then employed in the diggings. Mining in
this district (which was the true Golconda of medieval
history) has lately been revived in connection with gold
digging.
Rubies and occasional sapphires are the outcome of
the well-known, and perhaps over-rated, ruby mines of
Mogok, in Upper Burma, whilst sapphires and occasional
rubies are found in Ceylon. Within the area of peninsular
 India (especially towards the south) rubies are not
unknown, but they are not systematically collected. The
mines of Mogok are not the only mines in Upper Burma,
although they are the chief. There are mines also about
16 miles from Mandalay, in the Sagyin Hills, where the
red clay-covered limestone rocks are split and fissured
with cavities containing the detritus out of which rubies,
sapphires, and amethysts are washed. But the rubies are
of inferior quality ; all the best are found at Mogok.
These mines are about 70 miles north of Mandalay,