October 14, 1887.] 



SCIENCE. 



185 



as they are so portable, and there is no absolute necessity for records 

 being kept. The Indian trade-returns of the last three years give 

 the value of the imports at an average of _^2oo,ooo. A large trade 

 is carried on in them to Sewistan, Kashmir, Ladakh, Thibet, Ne- 

 paul, Sikkim, Upper Burma, Siam, and Karennee. There is no 

 doubt that through private sources four or five times the reputed 

 values are brought in, and also exported each year to Europe. 



There are in India three extensive tracts, widely separated from 

 one another, in which the diamond has been sought for. The name 

 of Golconda, originally applied to a capital town (now a deserted 

 fort in the neighborhood of Hyderabad), seems to have been used 

 for a whole kingdom ; but the town itself is many miles distant 

 from the nearest diamond-mines, and it was only the mart where 

 the precious stones were bought and sold. The second great tract 

 occupies an immense area between the Mahanuda and the Godav- 

 ery Rivers ; and the third great tract is situated in Bundelcund, 

 near the capital of which — Punnah — some of the mines are found. 

 For those content with a slowly paying occupation, and a hard life 

 involving close supervision of the workers, diamond-mining will 

 pay, provided such persons possess capital sufficient to last them a 

 few years. The diamonds now are usually brought from Parteal, 

 close to the southern portion of the Nizam's dominions. The deep- 

 est pits are not more than twelve feet. The matrix of the diamond 

 in those localities is a conglomerate sandstone. The appliances of 

 modern machinery for excavation, etc., directed by men of science, 

 may possibly bring to light gems that have not been discovered by 

 the rude native processes of search. 



It would be curious to ascertain the yield of diamonds in the 

 East from those mines in the last three hundred and fifty years, 

 and of Brazil in the last one hundred and fifty years since the dis- 

 covery there ; but no such data are obtainable, nor indeed can any 

 reliable estimate be formed of the value of the diamonds owned in 

 different countries. In the United States, diamonds to the value of 

 ;£i, 700,000 were imported in 1886. Two million and a half carats 

 of diamonds are cut yearly in Amsterdam. Precious stones being 

 free of duty in the chief European countries, no records are obtain- 

 able. The Brazilian mines are said to yield about _£8oo,ooo of dia- 

 monds, and India, Borneo, and Australia, ^200,000 ; but these 

 sums are insignificant now, in comparison with the South African 

 yield of about ;£4,ooo,ooo yearly. 



The only Indian mines now worked for diamonds are the 

 northern ones in Bundelcund. The produce, between ^£40,000 and 

 _£6o,ooo, is sold locally, and only about 100 carats are sent to Eu- 

 rope. Diamonds have been found in Sumatra and Celebes, but 

 Borneo alone now produces a regular supply, sending, it is com- 

 puted, about 3,000 carats annually into the European market. The 

 discovery of Cape diamonds has reduced the Brazilian mining to a 

 minimum of about 24,000 carats. And here it may be desirable to 

 explain what this fanciful diamond weight is. The diamond grain 

 is equal to about four-fifths of a troy grain, hence four diamond 

 grains are equal to one carat, or 3.174 troy grains. But, as half the 

 rough stone has to be cut away in polishing, to estimate the value 

 of a rough diamond we must ascertain its weight in carats, double 

 that weight, and multiply the square of this product by £2, which 

 may be taken as the average price of rough diamonds that are 

 worth cutting. Formerly, indeed, the price of diamonds was as 

 the square of their weight ; but this rule no longer holds good, as 

 their value mainly depends upon quality. 



From the four principal mines in Griqualand (which all lie within 

 a circle with a diameter of three miles), calculating the amount of 

 diamondiferous ground removed, and the known average yield per 

 load in each, it is found that not less than 33,000,000 carats of dia- 

 monds (or more than 6i tons weight) must have been extracted 

 since the first discovery ; realizing, in round numbers, ;^4o,ooo,ooo 

 sterling. 



The yield of diamonds from the Kimberley mine alone, from the 

 opening in 1871 to the end of 1885, is stated to have exceeded 17,- 

 500,000 carats, equal to 3+ tons weight of precious stones, in value 

 about ;£20,ooo,ooo. 



To obtain this, as many thousand tons of reef and ground have 

 had to be excavated. The mine is 450 feet deep, and the cubical 

 contents of this huge cavity measures about 9,000,000 cubic yards. 

 Four thousand Kaffirs are employed at this mine, and more than 



20,000 natives of Africa arrive yearly at the mines in search of 

 work; so that the employment of native labor and the development 

 of native trade are incidental benefits conferred on South Africa by 

 the discovery of the diamond-fields. 



The Dutch Government are the owners of the diamond-mines in 

 Borneo, which are situated in the district of Landak, in the terri- 

 tory of Ponteyanak : they are worked by Dyaks and Malays, but 

 with far superior skill by the Chinese. The gems are found in a 

 yellow-colored gravel, at depths ranging to 60 feet. Advances are 

 made to the miners, who are bound to deliver all stones at 20 per 

 cent below their market-value. 



Diamond-mining in New South Wales is likely to become of 

 much importance, and the colonists are sanguine of being able to 

 compete with South Africa in this trade. Twelve thousand dia- 

 monds have been obtained up to the present time, chiefly from the 

 tertiary gravels and recent drifts in the Bingera, Inverell, and Chit- 

 tagong districts. The largest diamond yet found weighed 16.2 

 grains, or about 5|- carats. They are of good color and quality. 

 Companies with large capital are forming to buy up and work the 

 extensive diamond-fields in Bingera. Other gem stones found in 

 that colony are garnets, the common emerald (green beryl), Ori- 

 ental emerald (green sapphire), royal blue sapphire, white and pale- 

 blue topaz, and agates. 



The ruby-mines of Burma, when scientifically worked, are des- 

 tined to yield a vastly increased quantity of this precious stone. 

 There has been lately a sharp competition for the lease of these 

 mines from the British Government, and it is believed that Messrs. 

 Streeter have secured the right for ^40,000. It is creditable to 

 England that they have such enterprising firms of jewellers, seeking 

 the produce at the very sources of production, as is evidenced by 

 their explorations in South Africa, their employment of fleets of 

 boats and divers for pearl-fishing round the Australian shores, and 

 competition against Indian and Continental firms for the Burma 

 ruby-mines. Rubies are of various reds, and the red sapphire or 

 Oriental ruby is next in value to the diamond. 



It has been well observed that digging for gems, like all gam- 

 bling speculations, is but too attractive, and great numbers of the 

 rural population in Ceylon and elsewhere neglect the safer pursuits 

 of agriculture for the speculative profits of the gem-pits. 



Ceylon has always had a reputation for its richness in precious 

 stones. Inferior kinds, such as the moonstone and the garnet, are 

 found in the beds of streams about Kandy, Newara Eleya, BaduUa, 

 and some of the small rivers of the south ; but the more precious 

 stones, such as the ruby, the blue sapphire, the Oriental topaz of 

 various yellows, the Alexandrite, and the cat's eye, must be sought 

 within a radius of thirty or forty miles from Ratnapura, the city of 

 gems. 



The Ceylon ruby is more frequently of a rich rose color, having 

 considerably more light and life than its Pegu rival, and is pre- 

 ferred by many Orientals to the pigeon-blood ruby, which, although 

 the more costly stone, is invariably less brilliant than the Ceylon 

 one. 



The search for gem stones is carried on in the most primitive 

 manner in Ceylon. The soil supposed to be rich in precious stones 

 is rented for an annual sum from the government. Coolies are set 

 to work to dig the earth, which is heaped up on one side, and then 

 washed through a trough with variously sized perforated zinc stops, 

 which retain all stones, according to their sizes. These are placed 

 on a table or flat surface, and the gems are easily distinguished and 

 picked out. The proportion of gems capable of being cut and 

 really marketable is not more than i per cent. 



Of the siliceous gems, the amethyst, of a purplish violet hue, 

 is the most valuable. The best amethysts are brought from Cam- 

 bay in India, and from Siberia, Ceylon, and Persia, where they are 

 found both lining the cavities of geodes and in rolled masses. The 

 chief supply of the blue turquoise is drawn from the peninsula of 

 Sinai, the great mining district of the ancient Egyptians. 



Among the Moors, rubies and emeralds, generally uncut, are 

 worn set in finger-rings and huge ear-rings, and necklaces of 

 amber and coral are also prized. The Moors consider that the 

 risk of fraud by imitation is lessened by not having precious stones 

 submitted to the art of the lapida;ry. This taste for keeping gems 

 in the rough also prevails among many of the Indian princes. 



