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Russian Gemstones Encyclopedia

Vladimir Bukanov. Russian Gemstones Encyclopedia

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LUDWIGITE


LUDWIGITE (Ludwigit—Ludwigite—Ћюдвигит) (Tschermak, G. 1874) after Ernst Ludwig (1842-1915), Professor of Chemistry, University of Vienna, Austria, who analyzed the discovered material. Borate – Mg2Fe3+O2|BO3], orthorhombic system. Hardness 5. Density 4.5-4.8. Glass luster to diamond one, silk one in aggregates. Ludwigite is found as columnar aggregates and twisted-fibrous complete masses. Crystals are rare. Color: dark green to black, more rare light green. Non-transparent. It is formed in the process of contact metamorphism in skarns and in other rocks. It resembles visually hedenbergite.

In Russia, ludwigite was found in the South Urals, at the Akhmatovskaya mine and in the Nyasemskie Mts., near Zlatoust. In Pribaikalia, in the Tazheranskiy alkali massif, they discovered titanic ludwigite. Findings of ludwigite are known in East Transbaikalia, at the deposits Zheleznyy Kryazh and Doninskoye. In Polar Yakutia, ludwigite is found as crystals up to 50 cm. long at the Titovskoye deposit, Tas Khayachtakh Ridge. In the basin of the Selennyakh River, along the spring Munlikan, they discovered massive black rock, composed with radial-rayed aggregates of ludwigite. Because of its ornamental properties it is used as an ornamental stone. In South Sakha (Yakutia), it was registered in association with pseudo-sinhalite at the Tayezhnoye deposit. Ludwigite was discovered in the western part of Romania in skarns as needle crystals up to 10 cm. at the Ocna de Fier (form. Moravica) deposit. In Pakistan, ludwigite as needle inclusions up to 2 cm. in transparent crystals of chrysolite in Sapat Valley, North West Prov., was discovered. In North Korea, Korean ludwigite at the Hol Kol deposit, near P’yöngyang, is found. Similar deposits are known in Japan in Pref. Iwate, Fukuschima and others. In U.S.A., blue carbonate rock with ludwigite, as an ornamental stone, was extracted at Crestmor deposit, Riverside Co., California, and others states.

Because ludwigite is found mainly as inclusions and complete rock masses, it is processed in cabochons.

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