178 SYSTEiMATIC DESCRIPllON OF PRECIOUS STONES 



prized " blue- white " being not of very great rarity. About 30 per cent, show a shght 

 tinge of colour, and though the remaining 30 per cent, have a pronounced colour, stones of 

 a deep and beautiful shade are rare. Next to colourless stones, those of a dull whitish or 

 greyish tint occur most frequently. The lighter tones of colour are, as we have already 

 seen, frequently confined to the surface of the crystal, which may be removed by grinding or 

 by the simpler process of burning, and thus the colourless heart of the crystal obtained. 

 Such stones, and also those in which the colour is confined to the edges and corners, have 

 been found in the district of Diamantina and especially in that of the Eio Pardo and the 

 Serra da Cincora. Deep tints of colour usually permeate the whole substance of the stone. 

 Diamonds which are differently coloured in different parts have also been met with. The 

 enclosure of foreign bodies in diamonds is frequently seen ; these may be dark in colour or 

 black, and sometimes resemble the moss-like markings of a moss-agate. The colours which 

 have been observed in Brazilian stones are yellow, red, brown, green, grey, and various shades 

 of black ; blue is rare, but a few stones showing a beautiful shade of this colour are said to 

 have been found. 



Passing now to the consideration of the general quality of Brazilian stones, it may be 

 stated that this on the whole is good, and surpasses that of Cape diamonds, which, as a rule, 

 have a yellowish tinge. The quality of Brazilian stones very nearly approaches that of 

 Indian diamonds, the best " blue-white " Brazilian diamonds being in no way inferior to the 

 choicest of Indian stones. 



The various diamond localities of Brazil do not, however, produce stones of uniform 

 quality ; the largest, most beautiful, and those most free from colour, have been found at 

 Bagagem. All the stones mined here do not by any means, however, tally with the above 

 description, many are coloured brown or black, and besides their undesirable colour often 

 exhibit an irregularity of form and numerous other small faults which combine to render 

 them of little value. The stones from the Canavieiras mines stand next in order of quality 

 to those from Bagagem. These, though small, possess a perfect whiteness, few faults, and 

 great regularity of form ; by daylight they exhibit a fine lustre and play of prismatic 

 colours ; by artificial light, however, these qualities are less marked and the stones compare 

 unfavourably with Cape diamonds. Diamantina takes the third place in the quality of the 

 diamonds it produces, and stones from different localities in the district show certain differ- 

 ences among themselves which are well known to the inhabitants ; thus some mines yield 

 white stones exclusively, others yield only coloured stones ; the latter, as a rule, predominate ; 

 the same applies also to the district of Grao Mogol. Diamonds from the Cincord district 

 rank lowest of all ; three-fourths of these are coloured, almost all are of irregular forms 

 unfavourable for cutting, and about one-half are fit only to be used as bort. The colour of 

 diamonds from Bagagem and Canavieiras is confined to the surface, which is usually bright 

 and only very seldom dull. The surface of stones from Diamantina is not infrequently 

 decidedly rough, it is seldom bright except when the stones have the form of a regularly 

 developed octahedron. 



T'Tie production of Brazilian diamonds has from the time of their discovery, about 

 1725, been very considerable. For the eighteenth century and the early decades of the 

 nineteenth century exact official returns were given, but for the years immediately following 

 the first discovery, and also for quite recent years, no absolutely reliable records exist, and 

 the various statements which are met with are based on more or less inaccurate estimates. 

 The official returns account only for stones acquired in a legitimate manner and, of course, 

 leave out of the calculation such as have been surreptitiously mined or obtained by dishonest 

 means. W. L. von Eschwege, at one time chief mining inspector in Brazil, estimated the 



