Page:Popular Science Monthly Volume 69.djvu/276

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THE best diamonds of the world, those of finest color and fire, come from Brazil, though most of the stones mined are small in size as compared with those from other sections. They occur in various places, more particularly Goyaz, Matto Grosso, Minas Geraes and Bahia. It is only in the latter two states in which they have been found in sufficient quantities to warrant mining.

The exact date of the discovery of diamonds in Brazil is unknown. At the end of the seventeenth century miners were taking out gold in Minas Geraes at Serro Frio and failed to recognize the diamonds which were occurring therewith. It is said that some stones were collected more because of their regularity and beauty of crystallization than from knowledge of their value. These in 1729 found their way to Portugal, where they were recognized as diamonds of unusual purity. The discovery caused quite a sensation at the court of King John V. There was a rush to the newly-discovered region, but the king so restricted mining that little was done until subsequent to 1832, when the present laws became effective.

Diamonds were first discovered in Bahia in 1840 at Santo Ignacio at the extreme northwest of the present region, but not until 1844, when discovery was made by a slave on the banks of the Mocojé river, the present location of São João do Paraguassú, was any great impetus given to mining. The mining area has gradually extended, but no new section was discovered until 1881 when by accident a find was made at Salobro, the diamonds of which usually take the name of Cannavieiras, the port to which they pay tribute.

The quality of Brazilian diamonds varies greatly with the locality in which found, while there is always a considerable difference between those of the same mine. In general, those from Minas Geraes are fairly assorted in quality, about Salobro (Cannavieiras) the beautiful whites and priceless blue whites predominate, while the other Bahia stones are inclined to be more off-colored and frequently contain black specks, thereby lowering their value.

The greater part of the Bahia diamonds differ from those found elsewhere in the world in that they frequently have a thin coat of surface color which gives the whole stone a bad appearance. This color will not yield to acids. To one particularly skilled, the under-