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Mineralogical ClassificationIMA 2014-046 = raisaite

17th May 2016 13:46 UTCMarco E. Ciriotti Manager

Reference:

▪ Pekov, I.V., Vlasov, E.A., Zubkova, N.V., Yapaskurt, V.O., Chukanov, N.V., Belakovskiy, D.I., Lykova, I.S., Apletalin, A.V., Zolotarev, A.A., Puschcharovsky, D.Y. (2016): Raisaite, CuMg[Te6+O4(OH)2]∙6H2O, a new mineral from Chukotka, Russia. European Journal of Mineralogy, 28, 459-466.

Abstract:

Raisaite, CuMg[Te6+O4(OH)2]∙6H2O, is a new mineral found at the Sentyabr’skoe deposit, Ilirney ore district, Western Chukotka, North-Eastern Region, Russia. It is associated with gypsum, malachite, azurite, cerussite, anglesite, brochantite, linarite, posnjakite, chlorargyrite, acanthite, gold, brucite, goethite, coronadite, paratellurite, and xocomecatlite in the oxidation zone of quartz veins with calcite, dolomite, ankerite, muscovite, pyrite, chalcopyrite, galena, sphalerite, hessite, petzite, altaite, primary acanthite and gold, etc. Raisaite occurs as prismatic crystals (up to 0.1 × 0.6 mm), as groups or crusts (up to 0.4 × 0.6 mm) and as dense roundish clusters (up to 0.2 mm in diameter) forming botryoidal aggregates (up to 1 mm across). Raisaite is transparent, light blue to bright sky blue, with a vitreous lustre. Its Mohs’ hardness is ca. 2. Cleavage is imperfect, probably on (100), the fracture is uneven. Dmeas = 2.82(1), Dcalc = 2.828g cm-3. Raisaite is optically biaxial (+), α = 1.626(3), β = 1.642(5), γ = 1.665(3) and 2Vmeas = 80(10)°. The IR spectrum is reported. The chemical composition (average of 7 analyses, H2O by difference) is: MgO 10.68, CurO 18.09, SO3 0.44, TeO3 41.19, H2Ocalc 29.60, total 100.00 wt%. The empirical formula calculated based on 12 O apfu is: Cu0.96Mg1.11Te0.99S0.02O4.20(OH)1.80∙6.00H2O. Raisaite is monoclinic, C2/c, a = 9.9078(2), b = 10.1325(3), c = 9.8375(2) Å, β = 91.839(2)°, V = 987.09(4) Å3 and Z = 4. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 7.088(100)(110), 5.815(35)(–111), 5.690(23)(111), 4.949(91)(200, 002), 4.507(50)(021), 3.533(17)(–202, 022), 3.358(17)(–221), 3.310(21)(221) and 2.694(29)(–132). The crystal structure (solved from single crystal X-ray diffraction data, R = 0.0186) is unique. It is based on heteropolyhedral zig-zag chains built by alternating edge-sharing Te6+O4(OH)2 and CuO4(H2O)2 octahedra. Mg(H2O)6 octahedra are connected with the chains from two sides via common O vertices. Adjacent chains are bound by H-bonding forming ‘‘layers’’ which are connected with each other by a system of H-bonds. The mineral is named in honour of the Russian mineralogist Raisa A. Vinogradova (born 1935), Moscow State University. Both the new mineral and its name have been approved by the IMA CNMNC (IMA 2014-046).

17th May 2016 16:38 UTCŁukasz Kruszewski Expert

Thanks for the upload. Mineral page improved.

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