Zhangpeishanite, BaFCl, a new mineral in fluorite from Bayan Obo, Inner Mongolia, China

Authors: Shimazaki, Hidehiko; Miyawaki, Ritsuro; Yokoyama, Kazumi; Matsubara, Satoshi; Yang, Zhuming

Source: European Journal of Mineralogy, Volume 20, Number 6, November 2008 , pp. 1141-1144(4)

Publisher: E. Schweizerbart'sche Verlagsbuchhandlung

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Abstract:

Zhangpeishanite, ideally BaFCl, occurs as inclusions up to 100 μm across in fluorite from Bayan Obo, Inner Mongolia, China. It is associated with barite, hematite and norsethite in fluorite. Zhangpeishanite occurs as transparent, colourless crystals with a white streak and vitreous luster. It is tetragonal, P4/nmm, a = 4.3951(8), c = 7.223(2) Å, V = 139.52(7) Å³, Z = 2. The five strongest lines in the powder XRD pattern are [d(Å), I/I₀, hkl]: (3.75, 100, 101), (3.11, 94, 110), (2.36, 82, 112), (2.79, 67, 012) and (1.898, 49, 211). The mean of twelve electron-microprobe analyses is (wt.%); Ba 70.90, F 9.88, Cl 18.85, and leads to the empirical formula Ba_0.99F_0.99Cl_1.02 on the basis of 3 apfu. Zhangpeishanite is a member of the matlockite group (Struntz-Nickel grouping 3DC.25), the Ba-dominant analogue of matlockite and rorisite. The calculated density of zhangpeishanite is 4.54 g/cm³. Zhangpeishanite is non-fluorescent. The hardness is 2½ on Mohs' scale (measured on a synthetic equivalent). The optical data obtained from the synthetic equivalent are: uniaxial ( - ), ω = 1.656(2), ε = 1.652(2) (589 nm).

Keywords: ZHANGPEISHANITE; NEW MINERAL; BAYAN OBO; MATLOCKITE GROUP; BARIUM FLUORIDE CHLORIDE

Document Type: Research article

DOI: http://dx.doi.org/10.1127/0935-1221/2009/0021-1888

Publication date: 2008-11-01

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