diamond
crystallized mostly in a residual magma before its ascent into the
pipes, and this residual magma rose and intermixed with the semiplastic
magma already filling the pipes.
IV. Distribution in India, Burma and Ceylon
India
was the first to produce the World's finest diamonds, which continued
till the second decade of the eighteenth century. During the sixteenth
and seventeenth "Centuries, there was the maximum production of several
hundreds of thousands of carats per annum, The output now is very small
and insignificant. Goleonda was the most famous for the largest and
best stones. In fact Goleonda formed the trade centre and not the mine
centre. The famous diamonds as the Koh-i-noor and the Pitt had their
origin in the Kistna district.
Tavernier,
a French traveller, made a number of voyages in the seventeenth
century, visited all the diamond mines and did considerable trade in
precious stones. He was the first
to
give ideas of these mines to the western countries. According to him,
most of the stones had their origin in the Kollur group, in the Guntur
district in South India, where he found 65,000 workers in 1645. The
mines had started work a hundred years previously. A full description
of the Indian diamond fields is given by V. Ball. Since then there have
been several, papers which contain descriptions of the ancient and now
defunct diamond fields of India. The places which were the most
productive in the past fall in 3 groups, each in association with the
old unfossiliferous rocks of pre-Cambrian age, known as the Furana
group comprising the Cuddapah and Karnul formations in South India and
the Vindhyan system in North India.
South India
The following districts were famous for diamond localities: e.g. Cuddapah, Anantapur, Bellary, Kurnool,
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