Belogubite, a New Mineral of the Chalcanthite Group from the Gaiskoe Deposit, South Urals, Russia

Belogubite CuZn(SO 4 ) 2 ⋅ 10H 2 O, a new mineral of the chalcanthite group, is found in the Gai (Gaiskoe) massive sulfide deposit, South Urals, Russia. This mineral forms aggregates of blue grains up to 1 mm. It is optically biaxial (–), n p = 1.512(2), n m = 1.525(2), n g = 1.531(2), 2 V = 70(10)°. The chemical composition of the holotype sample is as follows (wt %): 1.12 MgO, 0.10 MnO, 3.15 FeO, 8.98 CuO, 18.02 ZnO, 32.49 SO 3 , and 36.75 H 2 O, total 100.61. The empirical formula is (Cu 0.55 Zn 0.45 ) Σ1.00 (Zn 0.64 Fe 0.22 Mg 0.14 Mn 0.01 ) Σ1.01 S 1.99 O 7.98 ⋅ 10.02H 2 O. The crystal structure of belogubite is studied using the single crystal method, R = 0.016. The mineral is triclinic, P The unit cell parameters are: a = 6.2548(1), b = 10.6112(2), c = 6.0439(1) Å, α = 82.587(1), β = 109.625(1), γ = 104.848(1)°, V = 364.81(1) Å 3 , and Z = 1. The strongest reflections of the powder XRD pattern [ d meas. , Å ( I , %) ( hkl ) are: 5.73 (35) (100), 5.576 (47) (–110), 4.873 (100) (–111), 3.907 (31) (021), 3.719 (45) (0 –21), 3.229 (27) (111), 2.915 (25) (–221), and 2.684 (26) (130).