Spherocobaltite | |
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General | |
Category | Carbonate mineral |
Formula (repeating unit) | CoCO3 |
IMA symbol | Scbt[1] |
Strunz classification | 5.AB.05 |
Crystal system | Trigonal |
Crystal class | Hexagonal scalenohedral (3m) H-M symbol: (3 2/m) |
Space group | R3c |
Unit cell | a = 4.65, c = 14.95 [Å]; Z = 6 |
Identification | |
Formula mass | 118.94 g/mol |
Color | Most commonly dark magenta red; pink to red, brown, brownish red, grey, greyish red, velvet-black (due to surface alteration) |
Crystal habit | Encrustations - forms crust-like aggregates on matrix, crystals uncommon: rhombohedral to discoidal |
Cleavage | Perfect rhomboidal cleavage [2] |
Mohs scale hardness | 4 |
Luster | Vitreous |
Streak | Pink |
Diaphaneity | Transparent to translucent |
Specific gravity | 4.13 |
Optical properties | Uniaxial (–) |
Refractive index | nε = 1.600, nω = 1.885 |
Birefringence | 0.285 |
Pleochroism | Dichroic: O = violet-red; E = rose-red |
References | [2][3][4] |
Spherocobaltite or sphaerocobaltite is a cobalt carbonate mineral with chemical composition CoCO3. In its (rare) pure form, it is typically a rose-red color, but impure specimens can be shades of pink to pale brown. It crystallizes in the trigonal crystal system.