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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

PYROXMANGITE


PYROXMANGITE (Pyroxmangit—Pyroxmangite—ѕироксмангит) (Ford, W.E. & Bradley, W.M. 1913). Misnamed as being a manganese member of the pyroxene group; it is a pyroxenoid.

Composition & Properties. Silicate – (Ca,Mn)(Mn,Fe)6[Si7O21], subclass of chain silicate, triclinic system. It is represents a variety of ferrous rhodonite. Hardness 6. Density 3.9. Glass luster, nacre one. Cleavage in two directions. Pyroxmangite is a rare mineral, which is found in the form of table crystals and massive grained aggregates. Translucent to transparent. Color: from rose to brown.

Deposits. Pyroxmangite is a typical mineral of skarn manganese deposits, where it is found together with rhodonite. In Russia, at rhodonite deposits of the Middle Urals, pyroxmangite is a component of the rhodonite rock. However, in the South Urals, rhodonite is the basic component of orletz, at the Yuzhno-Faizulinskoye deposit, in the region of Sibay, pyroxmangite, rhodochrosite and quartz with admixture of hausmannite, tephroite, ribbeite and caryopilite are dominating. Here, rhodonite is a secondary mineral. In the South Urals, crystals of pyroxmangite, up to 15 cm. long, were found in amazonite pegmatites of the Ilmeny Mts. In the Primorskiy Region, it is found together with rhodonite at the Yuzhnoye deposit, near Dal’negorskoye. In Sweden, findings of massive red-brown pyroxmangite are known at the deposits Skotland and Tunaberg, Uppsala, and Långban, Värmland. There, it is called sobralit after the Swedish mineralogist J.M. Sobral. At deposits of Finland, pyroxmangite was discovered in brown crystals. In Romania, in the East Carpathian Mts., at the sedimentary manganese Râzoare deposit, they found columnar crystals of pyroxmangite up to 5 cm. long. In Japan, a transparent crystal of rose pyroxmangite, up to 4 cm. long, was found from the Taguchi mine, Aichi Pref.; and from a deposit on the Honshü Is. In Australia, findings of pyroxmangite crystals up to 20 cm. was found at the Broken Hill deposit, New South Wales. In the U.S.A., in Colorado, they are found in the Urey Silverton region. From that place massive material under the trade name “rhodonite” comes to the market. In Brazil, in Minas Gerais, at the deposits Conselhiero Lafaiette and Morro da Mina, they extract pyroxmangite together with rhodonite.

Gem-quality pyroxmangite is cut in cabochon like rhodonite. From transparent crystals they make small faceted gems up to 2 ct. for collection purposes.

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