Admontite
| Admontite | |
|---|---|
| General | |
| Category | Nesoborates |
| Formula (repeating unit) |
MgB6O10·7H2O[1] or MgB6O7(OH)6·4H2O[2] |
| Strunz classification | 6.FA.15 |
| Dana classification | 26.6.3.1 |
| Crystal system | Monoclinic |
| Crystal class |
Prismatic (2/m) H-M symbol: (2/m) |
| Space group | P21/c |
| Identification | |
| Color | colorless |
| Cleavage | Absent |
| Fracture | Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz) |
| Mohs scale hardness | 2 - 3 - Gypsum-Calcite |
| Streak | White |
| Density | 1.82 - 1.87, Average = 1.84 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.442 nγ = 1.504 |
| Birefringence | δ = 0.062 |
| Dispersion | None |
| References | [2][1][3] |
Admontite is a hydrated magnesium borate mineral with formula MgB6O10·7H2O.
Occurrence - In a gypsum deposit. Associations: gypsum, anhydrite, hexahydrite, löweite, eugsterite, pyrite, quartz.
It is named after Admont, Austria. Its Mohs scale rating is 2 to 3.
References
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