Coral is being 'utilized by the people of India in rapidly increasing quantities. In 1877-78, 65,527 lbs., value Rs. 6,90,875, were imported from the Mediter ranean, while in 1883 \the quantity was 152,372 lbs., value Rs. 19,59,367. small part is re-exported. Coral of a pale delicate ink colour is now the most valued in England, a large rop or bead selling at £30 to £40, and smaller pieces £120 to £150 the ounce.
Red is esteemed in India.
Corundum occurs in great a undance in Mysore, in the Coimbatore district of the Madras Presidency ; and its crystalline, translucent coloured varieties are the gems known to jewellers as the ruby, emerald, topaz, and sapphire. The emerald is one of the rarest of these varieties. The oriental ruby or red variety of corundum is very rare ; when pure in water and colour it is very valuable. The blue variety of corundnimis the oriental sapphire, is in greater abundance, but of inferior value, and its' colours greatly vary, from the deepest velvet blue to the palest and almost imperceptible tint, even losing all that and becoming colourless, and in that form is a very beautiful gem, remarkable for its white ness and the absence of prismatic colours.
The yellow variety of corundum is called the oriental topaz, which is of every shade of yellow, and when pure it is highly valued. But many stones have a milky opalescence, which makes them valueless. The ordi nary topaz of commerce, composed of silica and alumina, with hydrofluoric acid (hydric-fluoride), commonly of a pale orange, toning down to a straw colour, is of com paratively little value.
When the red and blue are mixed in the corundum, the stone is called oriental amethyst ; half a stone will be red and half blue, or emerald, ruby, topaz, and sapphire in the same stone. The Ceylon ruby has occasionally a blue tint, which can be expelled by heat. The opalescence occurs in rubies, sapphires, and topaz. When such stones are cut en cabochon at a certain angle to the axis, they form the star-stone, showing in a strong light a star of six rays, very pretty as a fancy stone, but of no value as a gem.
Diamonds are occasionally colourless. The most valuable diamonds are those known to merchants as blue-white. There are only in Europe three or four
diamonds which can be termed blue. The finest of these is the ' Hope ' diamond, valued at 230,000. It is of a beautiful sapphire blue.
A recent newspaper article mentions that 'a diamond, weighing 602 carats, of a dark slate colour, has been found in the Jagersfontein mine, South Africa. Owing to its peculiar colour, experts could fix no precise value, but it is said to be worth at least 22000. It is about the size of a duck's egg. Diamonds occur of a red colour ; one in London, weighing about three grains, is valued at 2800 ; and a diamond of a pure emerald green, the property of a W. Indian merchant, is mentioned by Mr. E. W. Streeter as of value £1000. At Banaganapilly black diamonds occur.
Among famed diamonds may be mentioned the Orloff gem possessed by the emperor of Russia, which is said to have been brought from Srirangam ; it weighs 1941 carats. The Regent or Pitt weighs 1361 ; it is said to have been obtained at Parteal ; but Mr. Pitt is also stated to have bought it for £12,500 from Jam Chund, a diamond merchant. The Sanci weighs 53i carats. The Matan diamond, belonging to a raja of Borneo, is of 367 carats, and valued at £269,379. The nizam of Hyderabad has one of 340 carats. The Rhodes diamond, of 150 carats, was found 12th February 1880 by Mr. Porter Rhodes in the Kimberley mine in South Africa. The last three are still (1883) uncut. The Pigot diamond weighs 82*. It was brought from India by Lord Pigot. In 1801 it was sold in a lottery for 750,000 francs. The Braganza was discovered in 1741 in Brazil. It weighed 1680 carats. If cut, it is supposed it would weigh 500 carats. It is believed to he a white topaz. The Star of the South, found in Brazil, weighs 254. It was found in July 1853 in one of the mines of the Bogagen district, in the Minas-Geraes province. About one-half of its weight was lost in cutting. Another Brazilian diamond, 138i carats, was found in 1775 by a negro, a few miles N. of the Rio Plata. One was found in 1878 at Du Toit's pan in S. Africa. It weighs 244 carats. The diamond known as the Star of South Africa was found there about 186$ ; it weighed 83 carats, and fetched £11,200.