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Russian Gemstones Encyclopedia

Vladimir Bukanov. Russian Gemstones Encyclopedia

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

HERDERITE


HERDERITE (Herderit—Herdérite—√ердерит) (Haidinger, W.K. 1828), after S.A.W. von Herder (1776-1838), mining official of Freiberg, Saxony, Germany. However, its first name was glucinite, It was connected with its presence in the composition of beryllium, which was earlier called glucine.

Composition & Properties. Phosphate – CaBe[(F,OH)|PO4], and hydroxylherderite – CaBe[(OH,F)|PO4], . monoclinic system. Hardness 5-5.5. Density 2.8-3.1. Glass luster. Cleavage in one direction. Herderite is a rare mineral, which is found in the form of short-prismatic crystals and bunch-like aggregates. Color: colorless, rose, yellow, green, violet or light blue. It forms a row of constant miscibility with hydroxylherderite.

Deposits. Herderite is found mainly in pegmatites. In Russia, in the Middle Urals, it was found in pegmatites of Mokrusha, near Yekaterinburg. On the Chukchi Penin., crystals of herderite up to 2.8 cm. long, available for faceting, at the deposits of cassiterite Iul’tin and Pervonachalnoye were found. In East Transbaikalia, by the railway station of Olovyannaya, in pegmatite occurs crystals of hydroxylherderite up to 2.5 cm. at the Little Kulinda mine. In East Kazakhstan, herderite was discovered at the Taldy Sai deposit, near Asu Bulak, Kalbinskiy Ridge. In Germany, herderite was found in Bavaria, at the deposits Waldstein and Epprechstein, Fichtelberg Mts. In Austria, herderite occur in crystals up to 5 cm. in pegmatite on Luftenberg, near Mauthausen. In India, Jammu and Kashmir (disputed area), herderite is represented with crystals up to 5x4x4 cm. at the Dusso deposit, Shigar Valley. In the U.S.A., in Maine, gem-quality pale colored crystals of herderite up to 5 cm. long at the deposits Stoneham and Mt. Apatate were found. In California, herderite gem-quality crystals of blue-green to lilac color, note more than 8x4 cm. was discovered in the region of Chihuahua Valley. In New Hampshire, it was found together with transparent prismatic crystals of hydroxylherderite up to 2 cm. long at the mines Palermo and Fletcher. From yellow-brown crystals of hydroxylherderite they made faceted stones more than 1 ct. In 1978, in Brazil, in Minas Gerais, at the Shanda mine, near Oro Preto, they discovered yellow-brown, lavender-blue and light bluish crystals of hydroxylherderite. The biggest of them was 18 cm. long, and 172 gm. in weight. In the same state, at the Virgem da Lapa deposit they found blue-green crystals of herderite more than 8 cm. long, as well as large crystals of scarlet hydroxylherderite. In the region of Governador Valadares, in pegmatite of Golconda, they also found brown crystals of hydroxylherderite up to 5 cm. long.

Cut Gems. Faceted gems of herderite and hydroxylherderite are usually not more than 5 ct. But from large crystals, extracted in Brazil, they can make faceted stones of more significant mass. In the Smiths. Inst., Wash., there is a faceted green herderite from Brazil in 5.9 ct. In Canada, in the Museum of Calgary, there is a blue Brazilian stone in 3.65 ct.

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