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Russian Gemstones Encyclopedia

Vladimir Bukanov. Russian Gemstones Encyclopedia

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JEREMEJEVITE


JEREMEJEVITE (Jeremejewit—Jéremejévite—≈ремеевит) (Damour, A. 1883), after P.V. Jeremejev (1830-1899), Russ. mineralogist and engineer, who first recognized the mineral. Borate – Al6[(F,OH)3|(BO3)5], hexagonal system. Hardness 7-7.5. Density 3.3. Glass luster. Jeremejevite is a rare mineral, which is found in the form of columnar crystals. Color: light blue to colorless, sometimes greenish-light blue. Central segments of crystals under the same composition sometimes are optically abnormal because of high inner tension. Such variety is called eichwaldite after the director of the Nerchinskiy mine D.J. Eichwald. In Russia, jeremejevite was discovered for the first in Transbaikalia, in the form of crystals up to 4.5 cm, in pegmatite of the Soktui Mt., Adun Chilon Ridge. As a gemstone, jeremejevite has obtained the recognition after its discovery in Namibia in 1974, in miaroles in pegmatite by Cape Cross, to the north-east from Swakopmund. They extracted its columnar colorless crystals there, as well as pale blue and pale yellow ones, up to 10x1.5 cm. Another finding of jeremejevite is known in Tadzhikistan, in the South-West Pamirs Mts., in miarolitic cavities in pegmatites of the Vez Dara deposit, where its columnar crystals reached the size of 20x4 mm. and were found together with pollucite. Later, similar crystals were discovered, in the East Pamirs Mts. There, in the pegmatite veins Priyatnaya and Fantaziya, on the southern slope of the Turakuloma Ridge, they found transparent crystals of jeremejevite up to 20 cm. long. Their color varies from colorless to pale yellow and pale blue.
Because of the small size of its crystals, jeremejevite is of collection interest only. Faceted stones are not more than 1.5 ct.
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