DIAMOND 347 DIAMOND terior may contain microscopic cavities and various inclusions, often black car- bon. It is the hardest substance known; but in spite of this hardness it is very brittle and cleavable; specific gravity, 3.52. It is generally colorless, but some- times tinged pink, red, orange, yellow, green, blue, brown, or black. Blue, red, and green are exceedingly rare colors. Light yellow, straw, and brown are the most common colors; rich yellow and browns are also highly prized. Some bluish-white Brazilian diamonds are phosphorescent in the dark after ex- posure to the sunlight. Originally dia- monds were preserved in their natural form, but in 1456 Louis de Berguin of Bruges discovered the art of polishing them on rotating disks with diamond dust. These circular disks, about 10 meters in diameter, are at the present time of soft steel covered with diamond dust and oil, and made to revolve at 3,000 revolutions a minute. This gives the diamonds the artistic smooth sur- faces and sharply defined edges. The process is slow and tedious, and requires great skill to produce fine results. Until a few years ago Amsterdam was the great diamond-cutting center of the world, but the finest cutting is now done in the United States, and in a great measure by machinery. As to the cut- ting process: Diamonds are, first, cleaved; that is, along the line of cleav- age of the stone a tiny cut is made by rubbing the stone with another dia- mond at the point where it is desired to cleave it, then a dull knife-edge is placed in the cut, and a sharp blow will sepa- rate the stone on a cleavage plane. Secondly, diamonds are cut by rubbing two diamonds together, the .stones being cemented with shellac to two pieces of wood or handles which are held in the hands, and rubbed together till they are of the desired form. This also has been superseded partly by an American ma- chine. Diamonds of from 1 to 22 carats each have been found in 24 localities in the United States, mapped by Kunz for the United States Geological Survey. The combustibility of diamonds was proved in 1694 by Averani and Targioni with the aid of burning glasses. That dia- monds turned to carbonic acid when burned was proved by Lavoisier in 1772. In 1867, in the S. of Africa, John O'Reilly, a trader and hunter, reached the junction of two rivers, and stopped for the night at the house of a farmer named Van Niekerk. Children were play- ing with some pebbles they had found in the river. O'Reilly took one of these pebbles to Dr. Atherstone, at Cape Town, who said that it was a diamond of 22 1^ carats. It was sold for $3,000. Niekerk remembered that he had seen an im- mense stone in the hands of a Kaffir witch-doctor, who used it in his incan- tations. He found the man, gave him 500 sheep, horses, and nearly all he pos- sessed for the stone, and sold it for $56,000. This was the famous "Star" of South Africa. It weighed 84 1/^ carats in the rough, and was found to be a gem quite the rival of an Indian stone in purity and brilliancy. After it had been cut it was bought by the Earl of Dudley, and is now known as the Dudley diamond. By 1869, parties in ox-wagons had worked their way over the plains to the Vaal river. Soon a tented city of 12,000 or more foreigners grew at Pniel and Klipdrift, on the op- posite banks of the stream, where dia- monds were found plentifully. The mines at Kimberley, 600 miles from Cape Town, are the richest in the world. The output of a single mine, the "Kim- berley," is $4,000,000 annually, and within 10 years this district has yielded about $58,000,000 in dividends. Ninety- five per cent, of all the diamonds pro- duced in the past 20 years came from South Africa. Most of the miners are natives, who are kept in compounds for periods of from three to six months; this system has broken up the illicit diamond buyers* ("I. D. B.") system, which seriously threatened the successful working of the mines. The life chairman of this sjmdi- cate was the Rt. Hon. Cecil J. Rhodes (q. v.), who by his genius and will created the corporation apparently out of chaos. The buying and selling of the gems is controlled by the government. The total value of all the diamonds known to exist in the world to-day is at least $1,000,000,000. It may safely be said that one-third of all the diamonds known are owned in the United States. Most of the great diamonds distin- guished for beauty and size have very interesting histories. One of the most famous is the Koh-i-Nur, or Koohinoor, "Mountain of Light." The legend is that it was carried 5,000 years ago by the hero Kama, whose deeds are celebrated in the "Mahabharata." It made its first appearance in history in the 14th cen- tury, when Ala-ed-din brought it to Delhi. At that time it was supposed to weigh 793 carats. When in 1673 the Grand Mogul sold it to Tavernier, it weighed only 279 carats, having been injured by the lack of skill of a Venetian lapidary. It was brought in 1739 at the sack of Delhi to Afghanistan. Thence it came into the possession of the East India Company, which presented it in 1850 to the English Crown. It was re-cut in
