Kasatkinite, Ba2Ca8B5Si8O32(OH)3 · 6H2O6, a new mineral from the Bazhenovskoe deposit, the Central Urals, Russia
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A new mineral, kasatkinite, Ba2Ca8B5Si8O32(OH)3 · 6H2O, has been found at the Bazhenovskoe chrysotile asbestos deposit, the Central Urals, Russia in the cavities in rhodingite as a member of two assemblages: (l) on prehnite, with pectolite, calcite, and clinochlore; and (2) on grossular, with diopside and pectolite. Kasatkinite occurs as spherulites or bunches up to 3 mm in size, occasionally combined into crusts. Its individuals are acicular to hair-like, typically split, with a polygonal cross section, up to 0.5 mm (rarely, to 6 mm) in length and to 20 μm in thickness. They consist of numerous misoriented needle-shaped subindividuals up to several dozen μm long and no more than 1 μm thick. Kasatkinite individuals are transparent and colorless; its aggregates are snow white. The luster is vitreous or silky. No cleavage was observed; the fracture is uneven or splintery for aggregates. Individuals are flexible and elastic. The Mohs’ hardness is 4–4.5. D meas = 2.95(5), D calc = 2.89 g/cm3. Kasatkinite is optically biaxial (+), α = 1.600(5), β = 1.603(2), γ = 1.626(2), 2V meas = 30(20)°, 2V calc = 40°. The IR spectrum is given. The 11B MAS NMR spectrum shows the presence of BO4 in the absence of BO3 groups. The chemical composition of kasatkinite (wt %; electron microprobe, H2O by gas chromatography) is as follows: 0.23 Na2O, 0.57 K2O, 28.94 CaO, 16.79 BaO, 11.57 B2O3, 0.28 Al2O3, 31.63 SiO2, 0.05 F, 9.05 H2O, −0.02 −O=F2; the total is 99.09. The empirical formula (calculated on the basis of O + F = 41 apfu, taking into account the TGA data) is: Na0.11K0.18Ba1.66Ca7.84B5.05Al0.08Si8.00O31.80(OH)3.06F0.04 · 6.10H2O. Kasatkinite is monoclinic, space group P21/c, P2/c, or Pc; the unit-cell dimensions are a = 5.745(3), b = 7.238(2), c = 20.79 (1) Å, β = 90.82(5)°, V = 864(1) Å3, Z = 1. The strongest reflections (d Å–I[hkl]) in the X-ray powder diffractions pattern are: 5.89–24, 3.48–2.1, 3.36–24; 3.009–100[\(12\bar 1\), 121, \(10\bar 6\)], 2.925–65[106, \(12\bar 2\), 122], 2.633–33[211, 124], 2.116–29[\(13\bar 3\), 133, 028]. Kasatkinite is named in honor of A.V. Kasatkin (b. 1970), a Russian amateur mineralogist and mineral collector who has found this mineral. Type specimen is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.
KeywordsDifferential Scanning Calorimetry Tourmaline Diopside Mineral Species Chrysotile
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- Antonov, A.A., Mineralogiya rodingitov Bazhenovskogo giperbazitovogo massiva (Mineralogy of rhodingites of the Bazhenovskoe deposit), St. Petersburg: Nauka, 2003.Google Scholar
- Efimov, V.I., Rodingite of the Bazhenovskoe chrysotileasbestos deposit, Ural Geol. Zh., 2004, no. 2(38), pp. 93–121.Google Scholar
- Erokhin, Yu.V., Cadaster of mineral species of the Bazhenovskoe deposit, in Mater. Ural’skoi mineralogicheskoi shkoly-1997 (Proceeding of Ural Mineralogical School-1997), Yekaterinburg: UGGGA, 1997, pp. 178–180.Google Scholar
- Erokhin, Yu.V. and Shagalov, E.S., Boron-bearing minerals of the Bazhenovskoe deposit resulted from effect of fluids derived from granite intrusion, in Problemy genezisa magmaticheskikh i metamorficheskikh porod (Genesis of igneous and metamorphic rocks), St. Petersburg, 1998, pp. 165–166.Google Scholar
- Mineralogiya rodingitov Bazhenovskogo mestorozhdeniya khrizotil-asbesta (Mineralogy of rodingites of the Bazhenovskoe chrysotile-asbestos deposit) O. K. Ivanov, E.M. Spiridonov, and V.G. Krivovichev, Eds., Yekaterinburg: UGGGA, 1996.Google Scholar
- Popov, V.A., Tochilinite, twins of diopside, brucite, chabasite, and harmotome from rodingites of the Bazhenovskoe deposit, Ural. Miner. Sb., 1995, no. 5, pp. 139–144.Google Scholar
- Sokolov, Yu.A. and Luzin, V.P., Boron (astrakhanite) mineralization in serpentinites of the Bazhenovskoe chrysotileasbestos deposit, Izv. AN SSSR, Ser. Geol., 1981, no. 9, pp. 133–136.Google Scholar
- Zoloev, K.K., Chemyakin, V.I., Shmaina, M.Ya., et al., Bazhenovskoe mestorozhdenie khrizotil-asbesta (The Bazhenovskoe chrysotile-asbestos deposit), Moscow: Nedra, 1985.Google Scholar