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98
THE MINERAL WEALTH OF BRAZIL
 
 

 
 
carbonados approximates the total in practically all years and thus furnishe an index as to the trends in the industry.
Annual exports of precious stones in the 1920-9 decade averaged 15,945 contos while in the 1930-4 quinquennium, there was a drastic decline to 1,669 contos and in the 1935-9 five-year period, they increased again to average 16,351 contos. In the first mentioned period, carbonado exports were larger than that of diamonds accounting for 40% of the total whiie that of diamonds amounted to 31%. Other gemstones represented 29% of the total. In the following five-year period, carbonados accounted for a larger percentage share amounting to 55% while the diamonds represented 41%. It is only in the 1935-9 period that there is a distinct domination of the trade by diamonds (94% of the total) due largely to the extraordinarily large shipments of 1939. Car-bonados in this period represented but 2% of the total. It may be noted that in 1940, the total exports of this nature consisted of diamonds and carbonados only, that of the former being 81,403 contos while the latter amounted to 1,180 contos.
From the above trends, to all appearances, the importance of carbonados has declined to new levels despite the perceptible increase in the last few years. One significant reason for this change is evident in the growing use of borts and the smaller diamonds in the place of carbonados. According to the Minerals Yearbook, 1940, smaller stones are said to be sounder and harder than the larger. There is the additional discovery of a new cast-setting metal of be-ryllium-copper which permits the use of small diamonds and which will no doubt greatly affect the trade in carbonados.
Imports of precious stones vary but slightly although there is a notice able decline in the five years from 1930 to 1935 in which they averaged 840 contos as compared to the 1,400 contos of the previous decade and 1,600 contos ; for the quinquennium 1935-9. In 1940, the imports amounted to 499 contos.
DIAMONDS
The uses of diamonds are- divided between the industrial applications and that for ornament. However with the fears of contingencies arising from the "unexpected", diamonds have lately served another purpose, such as that as an investment for capital.
The discovery of diamonds in Brazil dates back to 1729 and their exploitation from that date in the state of Minas Gerais became one of the most important activities of Colonial Brazil.
This country soon became the world's principal producer of diamonds. The stones acquired an excellent reputation for their unequalled clearness and brilliancy and competed on even terms with the diamonds of Hyderabad, India whose mines at Golconda served as a standard for Brazil. It may be said that the world-wide popularization of this gem was due to its discovery in Brazil;