Calcite is an extremely common rock-forming mineral. Exceptionally diverse in crystal form. It is varied in color, but the base color of calcite without impurities is white or colorless. One of the minerals on the Mohs hardness scale is hardness 3. It has a number of varieties, for example, Icelandic spar is a transparent variety of calcite.
You can see calcite stone for sale and buy it in the Minerals of Russia online store.
General | |
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Category | Carbonate minerals |
Formula (repeating unit) |
CaCO3 |
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 = 4.9896(2) Å, c = 17.0610(11) Å; Z = 6 |
Identification | |
Color | Typically colorless or white - may have shades of various colors |
Crystal habit | Crystalline, granular, stalactitic, concretionary, massive, rhombohedral |
Twinning | Common by four twin laws |
Cleavage | Perfect on {1011} three directions with angle of 74° 55' |
Fracture | Conchoidal |
Tenacity | Brittle |
Mohs scale hardness | 3 (defining mineral) |
Luster | Vitreous to pearly on cleavage surfaces |
Streak | White |
Diaphaneity | Transparent to translucent |
Specific gravity | 2.71 |
Optical properties | Uniaxial (−) |
Refractive index | nω = 1.640–1.660 nε = 1.486 |
Birefringence | δ = 0.154–0.174 |
Solubility | Soluble in dilute acids |
Other characteristics | May fluoresce red, blue, yellow, and other colors under either SW and LW UV; phosphorescent |