Vishnevite
Appearance
Vishnevite | |
---|---|
General | |
Category | Tectosilicate |
Formula (repeating unit) | (Na,Ca,K)6(Si,Al)12O24[(SO4),(CO3),Cl2]2-4·nH2O |
Strunz classification | 9.FB.05 |
Crystal system | Hexagonal |
Crystal class | Pyramidal (6) H-M symbol: (6) |
Space group | P63 |
Unit cell | a = 12.7228(3) c = 5.198(3) [Å]; Z = 1 |
Identification | |
Color | Colorless, light blue, orange-yellow, white |
Cleavage | Perfect |
Mohs scale hardness | 5 - 6 |
Luster | Vitreous, pearly |
Streak | White |
Optical properties | Uniaxial (-) |
Refractive index | nω = 1.490 - 1.507 nε = 1.488 - 1.495 |
Birefringence | δ = 0.002 - 0.012 |
Vishnevite, or sulfatic cancrinite, is a mineral of the cancrinite group with the chemical formula (Na, Ca, K)6(Si, Al)12O24[(SO4),(CO3), Cl2]2-4·nH2O. It has hexagonal crystals.[1][2]
References
- ^ Fleischer, Michael & Mandarino, Joseph, "Glossary of Mineral Species", The Mineralogical Record, 1991
- ^ Webmineral data