Star-stones are varieties of the corundum class of precious stones,—star-rubies, star-sapphires, and the star-topaz. They have stars of six rays, but are not esteemed by the Singhalese or natives of India.
Topaz occurs in the corundum localities. Oriental topaz is a variety of corundum of a yellow colour, more or less mixed with red. The most esteemed colour is a bright jonquil-yellow, and next a pure lemon-yellow. It is a very beautiful stone, though inferior in value to emerald, ruby, or sapphire. The kind most valued by the jewellers of Europe are brought from the Urulga river. White topaz is a fluo-silicate mixed with silicate of aluminium.
Tourmaline occurs abundantly in Siberia, in Burma, in Dindigul, and in Ceylon, in colours black, brown, blue, green, red, white, and colourless, and exhibiting a dichroism. The tourmalines have many valuable and beautiful forms, made use of in the arts. Rubellite, variety of tourmaline, is found in Burma and Siberia..
Turquoise, from Central Asia, is a favourite with the Muliammadans of India. Turquoise is the Firozah, HIND., hence Firoza-rang, turquoise blue. It is found at Khojend, in Mawar-al-nahr or Trans-Oxiana, at Shebavek, in Kirman, and in a mountain of A zerbijan, where the mine was discovered about fifty years before Alimad bin Abd nl Aziz composed his Treatise on Jewels. He describes the mine at Nishapur as most celebrated from early ages for that particular kind of turquoise entitled Abu Ishaki, which, says be, averts evil from those who wear it, conciliates the favour of princes, augments wealth, preserves the sight, ensures victory over an adversary, and banishes all unpleasant dreams. He says the ancient sages, when first they
beheld a new moon, immediately after fixed their eyes on the Firozah (Ouseley, Tr. i. p. 211). Turquoise is apt to change colour if brought into contact with acids, musk, camphor, or scents. Small clear Persian stones at Nishapur in Khorasan sell at fid. to 20s. each, whilst a fine ring stone will realize from £10 to £40. A perfect stone of the size of a shilling, and of good depth, was sold for £400. It varies from white to a fine azure blue, but it is only the fine blue stones that arc of value.
Zircon occurs in alluvium in the Ellore district. Hyacinth of the lapidary and jargoon are varieties of zircon. Its pellucid varieties are gems.
—Prinsep's Oriental Accounts of the Precious Minerals ; Ouseley's Tr.; C. TV. King, Precious Stones ; Emmanuel on Gems; Mason's Bin-mah ; Tennant's Ceylon; Dr. Buist in Bombay Times ; Tavernier's Travels; Niebuhr, Beschreibung von des Arabien ; Davy's Ceylon, p. 20; xxxvii., xv., xxiii; Forbes' Eleven Years in Ceylon, ii. p. 97 ; IVellsted, i.r.p. 112, 113 ; Mr. Streeter; .11h•. V. Ball on Diamonds, etc.