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NON- METALLIC MINERALS
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until that time diamonds were a monopoly of the Orient and their use restricted to the aristocratic class.
Brazil
and India which were the principal diamond fields in the Eighteenth
and Nineteenth Centuries, later ceded their position of leading
importance to Africa which subsequently became the Diamond Continent
with the discovery of the precious gems in the Cape Colony, Transvaal
and in the Orange Free State.
In
1870, with the discovery of large diamond reserves in primary
deposits, the Union of South Africa commenced to exert an enormous
influence on the diamond market. From that time on, diamond regions
dependent on alluvial production dropped to a secondary position.
Included in the latter group is'Brazil which, since that time, has
never been able to regain her former position as leader. In Hyderabad,
India, diamond mining has declined almost to the point of disappearing.
The
best-known alluvial diamonds zones in Brazil are distributed among the
following states: Minas Gerais, Baia, Mato Grosso, Goiaz, Amazo-bias,
Parana and Sao Paulo.
In
the state of Minas Gerais the principal diamond alluvials are found in
Diamantiua, Grao Mogol, Sao Jose da Chapada, Serra do Cabral, Abaete,
Coromandel and Estrela do Sul.
The
town of Tijuco, today Diamantina, was the principal diamond-mining
center in Colonial times, and today is the center of a scientific
research to determine the development or genesis of Brazil's diamond
deposits.
The
region of Sao Joao da Chapada, well-known for the primary deposits of
precious stones, possesses several occurrences that of Campos do
Sam-paio being the most important. Its production averages 100 carats a
month and has been in continual operation over a long period.
In
the diamond field of Estrela do Sul, there was discovered in 1854, the
celebrated diamond of 254.40 carats which is known under the name of
the place of origin.
Lately,
production in the state of Minas Gerais has been more intense in the
regions of Tiros, Patos and Coromandel. In 1938, there was found in
Coromandel the largest diamond ever to appear in Brazil. It weighed
726.60 carats and was named the Presidente Vargas. In the same regions the Coromandel diamond weighing 400.65 carats and the Darcy Vargas of 460 carats were found, the latter being the second largest diamond ever found in Brazil.
The
discovery of the first diamonds in the vicinity of Mocuge in the state
of Baia, in 1844, caused a rush in which the prospectors established
themselves permanently so that even to this day it is still one of the
most important diamond districts of Brazil. Its population of 20,000
persons increased, between 1844 and 1848 to 50,000. It was a rush in no
way inferior to those for the search of gold in California and in
Australia.
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