Usovite

General Information: Chemical Formula:Ba2CaMgAl2F14 Composition:(Molecular Weight = 658.98 gm)Barium 41.68 % BaCalcium 6.08 % CaMagnesium 3.69 % MgAluminum 8.19 % AlFluorine 40.36 % F  Empirical Formula: Ba2CaMgAl2F14 Environment:Fluorite veins. IMA Status:Approved IMA 1967 Locality:Upper Noiby River area, Yenisei region, Siberia, Russia. Name Origin:Named for Mikhail Antonovich Usov (1883-1939), Russian geologist.Physical Properties: Cleavage:[???] Perfect Color:brown, dark brown, or yellowish brown. Density:4.18 Diaphaniety:Translucent to Opaque Habits:Granular - Generally occurs as anhedral to subhedral crystals in matrix., Platy - Sheet forms (e.g. micas)., Hardness:3.5 - Copper Penny Luster:Vitreous - Greasy Streak:whiteMore details...