210 SYSTEMATIC DESCRIPTION OF PRECIOUS STOxNES 



The most salient feature of the South African diamond-fields, as compared with those 

 of other countries, is the prevalence of stones of large size. It will be remembered that 

 in Brazil the discovery of a stone of 17 carats was such an event that its finder, if a slave, 

 was rewarded with his freedom. In South Africa stones of this size occur in hundreds and 

 in thousands ; and the discovery of a stone of 100 carats causes less excitement than did the 

 findina: of a 20-carat stone in Brazil. Stones of 80 to 150 carats are of common occurrence, 

 scarcely a day passes in which a stone between 50 and 100 carats in weight is not brought to 

 light. Since the year 1867, when the South African deposits were discovered, the number of 

 large stones, which have been found there, far exceeds not only the number unearthed in India 

 in the course of a thousand years and in Brazil during a period of 170 years, but also the total 

 production of large stones in these two countries added together. Diamonds which weigh 

 after cutting upwards of 75 carats have occurred at the Cape in greater numbers than in 

 any other known locality. While the mean size of Brazilian diamonds is scarcely one carat, 

 the majority of South African stones are of this or larger size, excepting, of course, those 

 stones which are rejected as being unsuitable for cutting. 



We have already mentioned that the largest diamond known, the " Excelsior," was 

 found at the Jagersfontein mine in 1893. It is a stone of the first water, weighing 971| 

 carats, and will be described and figured (Fig. 51) in the section dealing with large diamonds. 

 The next largest Cape diamond is the one of 655 carats found in the same mine in 1895, 

 which is stated to be of unusually fine quality. Another stone of 600 carats, but of poor 

 quality, is said to have been found in this mine. A stone of 457| carats was found in one 

 of the mines, but which one is not recorded ; one almost as large, weighing 428^ carats, was 

 obtained from the De Beer's mine, while in 1892 the Kimberley mine yielded a diamond of 

 474 carats, from which was cut a brilliant weighing 200 carats. " The Julius Pam," a stone 

 of 241|^ carats, which gave a brilliant of 120 carats, came from the Jagersfontein mine. A 

 few large stones have also been contributed by the river diggings, the largest being the 

 " Stewart" of 288|- carats, which was cut as a brilliant weighing 120 carats. 



Although the diamond-fields of South Africa are unique as concerns the number and 

 size of the stones found there, the same can by no means be said of the quality of diamonds 

 from this region. Not only are the stones frequently so dark and unpleasing in colour 

 that they can only be applied as bort for technical purposes, but they are also very often 

 disfigured by " clouds " and cracks, the so-called " feathers." Moreover, these cracks, 

 especially in stones from the Du Toit's Pan mine and from the diggings on the Vaal 

 River, are often rendered still more conspicuous by being filled with films of limonite. 

 The presence of enclosures of foreign matter is also common ; these are usually black 

 and resemble particles of coal, but are probably haematite or ilmenite. There are also 

 green enclosures of a pecular vermiform character, which, according to Cohen, are probably 

 some compound of copper, and red enclosures of unknown nature. It is stated by Streeter 

 that on an average only 20 per cent, of Cape stones are of the first water, 15 per cent, 

 of the second, and 30 per cent, of the third, the remaining 35 per cent, being bort. 

 According to Kunz, however, only 8 per cent, are of the first quality, 25 per cent, of the 

 second, and 20 per cent of the third quality, the remainder being bort. 



Cape diamonds show a great range of colour. Perfectly colourless or pure white to 

 deep yellow, light to dark brown, green, blue, orange, and red specimens have all been 

 found. At the same time the stones may be transparent and clear or cloudy and 

 opaque. 



Pure white, absolutely colourless stones are very rare, still the finest blue-white diamonds, 

 such as are found in India and Brazil, are not altogether absent. Only about 2 per cent, of 



