DIAMOND: OCCURRENCE IN BRAZIL 173 



flocked in thousands to the place. According to some accounts, as many as 25,000 people 

 had settled in the neighbourhood in the following year ; other estimates, however place the 

 number at from 12,000 to 14,000. Many of these fresh arrivals came from the Serra da 

 Chapada and the Serra do Assuaria, where, in consequence of the stream of emigration, 

 diamond -mining was almost entirely abandoned ; the majority, however, were workers from 

 Minas Geraes, where the yield of diamonds had long been gradually diminishing. 



The yield of the newly discovered fields was very rich and raised the ever sinking 

 diamond production of Brazil to its former high level. It is said that during the most 

 productive period the daily yield averaged 1450 carats ; soon, however, the yield began to 

 decrease and the number of workers fell to 5000 or 6000. Up to the year 1849 the total 

 output of diamonds of this district was 932,400 carats, and this immense production had 

 lowered the prices of the stone fifty per cent. According to the estimates of diamond 

 merchants, Bahia produced in the year 1858 54,000 carats, while from Diamantina came 

 only 36,000 carats. 



The occurrence of diamond in the Serra da CincorA is confined to the alluvial deposits 

 of the rivers. According to J. J. von Tschudi, who quotes the statement of the traveller 

 V. von Helmreichen, the first discovery was made on the banks of the Macuje, a small 

 tributary on the right bank of the Paraguassii. Here, besides a few small villages, there 

 sprang up in consequence of the finds the principal town of the district, Santa Isabel de 

 Paraguassii (also known as Comercio), lying about 190 miles to the west of the town of 

 Bahia. Later, diamonds were discovered at a distance of forty-five miles from Santa Isabel. 

 The principal place to the north of Santa Isabel is Lenpoes, in the neighbourhood of which 

 is Monte Vereno, a well-known diamond locality, where the diamond sands consist largely of 

 fragments of itacolumite. Other important localities are Andrahy, Palmeiros, San Antonio, 

 and San Ignacio. 



The washings on the west side of the Serra have been poor ; a considerable number of 

 diamonds were, however, obtained from the Macuje itself and from those parts of the 

 Paraguassii and Andrahy rivers which cut through the Serra. On the latter river, the 

 principal washings are situated on the small tributary streams of its right bank. In the 

 bed of the Paraguassii river are depressions rich in diamonds similar to those found in the 

 diamond rivers of Diamantina. 



Diamonds from the Serra da Cincord are known as " Cincora (SincorA) stones," or 

 as " Bahias, " in order to distinguish them from the " Diamantina stones." They are 

 considerably inferior in quality to the latter and command a much lower price. They 

 are usually coloured yellow, green, brown, or red, and almost all have an elongated, irregular 

 form which makes them less suitable for cutting. Diamonds of the purest water are 

 rarer here than elsewhere in Brazil, and in size they are usually small, the large stone of 87| 

 carats found at the beginning of the fifties being an exception to the general rule. 



It is in the diamantiferous district of Cincora that the peculiar variety of diamond 

 mentioned several times above, namely, the black carbonado (" carbonate "), is almost 

 exclusively found. Although found in association with the ordinary diamond, it is so utterly 

 unlike it in appearance that it might be taken for anything rather than diamond. 



In contrast to the ordinary diamond, carbonado very rarely exhibits a crystalline form 

 of any regularity, still the octahedron, rhombic dodecahedron, and the cube, with rough faces 

 and rounded edges and corners, have been observed. A crystal of carbonado with the form 

 of a cube is represented in Plate I., Fig. 4. The substance occurs much more frequently, 

 however, in irregular rounded nodules, varying in size from that of a pea to a mass exceeding 

 a pound in weight. The average weight of the nodules is 30 to 40 carats, but specimens 



