Nabimusaite
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CategorySilicate mineral, nesosilicate
FormulaKCa12(SiO4)4(SO4)2O2F
| Nabimusaite | |
|---|---|
| General | |
| Category | Silicate mineral, nesosilicate |
| Formula | KCa12(SiO4)4(SO4)2O2F |
| IMA symbol | Nbm[1] |
| Crystal system | Trigonal |
| Crystal class | Hexagonal scalenohedral (3m) H-M symbol: (3 2m) |
| Space group | R3m |
| Unit cell | a = 7.19, b = 7.19 c = 41.25 [Å] (approximated); Z = 3 |
| Identification | |
| Color | Colorless |
| Cleavage | (001), imperfect |
| Tenacity | Brittle |
| Mohs scale hardness | 5 |
| Luster | Vitreous |
| Streak | White |
| Density | 3.12 (calculated) (approximated) |
| Optical properties | Uniaxial (-) |
| Refractive index | nω=1.64, nε=1.64 (approximated) |
| References | [2][3] |
Nabimusaite is a very rare mineral with formula KCa12(SiO4)4(SO4)2O2F.[2] Its structure, as in case of similar aradite and zadovite, is a derivative of the one of hatrurite.[4] Nabimusaite gives its name to the nabimusaite group.[5] The mineral was found in a pyrometamorphic rock of the Hatrurim Formation, a site known for the natural pyrometamorphism. It is interpreted to have formed due to interaction of a precursor assemblage with sulfate-rich melt.[2] Nabimusaite is potassium- and fluorine-analogue of dargaite.[6]
Nabimusaite was discovered in nodules composed of larnite and ye'elimite, in a rock formed due to pyrometamorphism.[2]
Notes on chemistry
Nabimusaite is impure as it has a phosphorus admixture.[2]
