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Russian Gemstones Encyclopedia

Vladimir Bukanov. Russian Gemstones Encyclopedia

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SINHALITE


SINHALITE (Sinhalit—Sinhalite——инхалит) (Claringbull, G.F. & Hey, M.H. 1952), from Sanskrit “Sinhala”, where the mineral was found. Borate. – MgAl[BO4], orthorhombic system. Hardness 6-7. Density 3.48-3.50. Glass luster. Color: yellowish-brown to golden, fire-orange to dark brown, more rarely brown-rose and rose. Transparent. The nature of its color is connected with the iron admixture. It displays obvious pleochroism from pale brown to dark brown. Sinhalite is a rare mineral, which was discovered at first on placers of Sri Lanka in the form of gravel pebbles up to 4 cm. in size. Earlier, it was taken for chrysolite and it was called brown peridote. It looks like zircon and brown chrysoberyl, too. It was formed under contact metamorphism. In Russia, sinhalite in skarn Taëzhnoye deposit, Aldan Plateau, Sakha (Yakutia), occur. Beside placers of Sri Lanka, gem-quality crystals were found on placers of Myanmar (Burma). In Tanzania, in skarn, in the contact with granites, in the Handeni Dist., they found rose and rose-brown crystals with transparent segments, available for faceting. In the U.S.A., sinhalite at Johnsburg, Warren Co., New York, was found; and also near Hamburg, Sussex Co., New Jersey.

Faceted stones are up to 20 ct., rarely more than 100 ct. In the Museum of Calgary, Canada, they expose a faceted brown-rose sinhalite from Sri Lanka in 24.76 ct. In the Smiths. Inst., Wash., there are two brown sinhalites from Sri Lanka in 43.5 and 109.8 ct. The biggest stone in 158 ct. is kept in a private colletion.

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