Comparatively uncommon as sapphires are in the Burma mines a faultless stone, weighing as much as 79½ carats, has been discovered there.
Good rubies, mostly darker in colour than the Burmese stones, are found in considerable quantity near Bangkok in Siam, Chantabun being the centre of the trade, where, just as in Burma, they are intimately associated with the red spinel. Because of the difference in tint and the consequent difference in price, jewellers draw a distinction between Burma and Siam rubies; but that, of course, does not signify any specific difference between them. Siam is, however, most distinguished as the original home of splendid sapphires. The district of Bo Pie Rin in Battambang produces, indeed, more than half the world’s supply of sapphires. In the Hills of Precious Stones, such being the meaning of the native name for the locality, a number of green corundums are found. Siam also produces brown stones characterized by a peculiar silkiness of structure. Rubies are found in Afghanistan at the Amir’s mines near Kabul and also to the north of the lapis lazuli mines in Badakshan.
The conditions in Ceylon are precisely the converse of those obtaining in Burma; sapphire is plentiful and ruby rare in the island. They are found in different rocks, sapphire occurring with garnet in gneiss, and ruby accompanying spinel in limestone, but they come together in the resulting gravels, the principal locality being the gem-district near Ratnapura in the south of the island. The largest uncut ruby discovered in Ceylon weighed 42½ carats; it had, however, a decided tinge of blue in it. Ceylon is also noted for the magnificent yellow corundum, ‘oriental topaz,’ or, as it is locally called, ‘king topaz,’ which it produces.
Beautiful sapphires occur in various parts of India, but particularly in the Zanskar range of the north-western Himalayas in the state of Kashmir, where they are associated with brown tourmaline. Probably most of the large sapphires known have emanated from India. By far the most gigantic ever reported is one, weighing 951 carats, said to have been seen in 1827 in the treasury of the King of Ava. The collection at the Jardin des Plantes contains two splendid rough specimens; one, known as the ‘Rospoli,’ is quite flawless and weighs 13215/16 carats, and the other is 2 inches in length and 1½ inches in thickness. The Duke of Devonshire possesses a fine cut stone, weighing 100 carats, which is brilliant-cut above and step-cut below the girdle. An image of Buddha, which is cut out of a single sapphire, is exhibited, mounted on a gold pin, in the Mineral Gallery of the British Museum (Natural History).
For some years past a large quantity of sapphires have come into the market from Montana, U.S.A., especially from the gem-district about twelve miles west of Helena. The commonest colour is a bluish green, generally pale, but blue, green, yellow and occasionally red stones are also found; they are characterized by their almost metallic lustre. With them are associated gold, colourless topaz, kyanite, and a beautiful red garnet which is found in grains and usually mistaken for ruby. Rubies are also found in limestone at Cowee Creek, North Carolina.
Blue and red corundum, of rather poor quality, has come from the Sanarka River, near Troitsk, and from Miask, in the Government of Orenburg, Russia, and similar stones have been known at Campolongo, St. Gothard, Switzerland.
The prolific gem-district near Anakie, Queensland, supplies examples of every known variety of corundum except ruby; blue, green, yellow, and parti-coloured stones, and also star-stones, are plentiful. Leaf-green corundum is known father south, in Victoria. The Australian sapphire is too dark to be of much value.
Small rubies and sapphires are found in the gem-gravels near the Somabula Forest, Rhodesia.