Zhangpeishanite, BaFCl, a new mineral in fluorite from Bayan Obo, Inner Mongolia, China
Shimazaki, Hidehiko; Miyawaki, Ritsuro; Yokoyama, Kazumi; Matsubara, Satoshi; Yang, Zhuming
European Journal of Mineralogy Volume 20 Number 6 (2008), p. 1141 - 1144
published: Dec 15, 2008
ArtNo. ESP147052006014, Price: 29.00 €
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 Ba0.99F0.99Cl1.02 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).