Poudretteite
Сyclosilicate mineral
From Wikipedia, the free encyclopedia
Poudretteite is an extremely rare mineral and gemstone that was first discovered as minute crystals in Mont St. Hilaire, Quebec, Canada, during the 1960s.[6] The mineral was named for the Poudrette family because they operated a quarry in the Mont St. Hilaire area where poudretteite was originally found, and the quarry is currently owned by the United Kingdom based Salmon Mining Industries Inc. Poudretteite has a barely detectable radioactivity.[7]
| Poudretteite | |
|---|---|
| |
| General | |
| Category | Cyclosilicate |
| Formula | KNa2B3Si12O30 |
| IMA symbol | Pou[1] |
| Strunz classification | 9.CM.05 |
| Dana classification | 63.02.01a.08 |
| Crystal system | Hexagonal |
| Crystal class | Dihexagonal dipyramidal (6/mmm) H-M symbol: (6/m 2/m 2/m) |
| Space group | P6/mcc |
| Unit cell | 1,221.72 ų |
| Identification | |
| Color | Colorless, Light pink |
| Crystal habit | Roughly equant barrel-shaped prismatic crystals |
| Cleavage | None |
| Fracture | Conchoidal, splintery |
| Tenacity | Brittle |
| Mohs scale hardness | 5 |
| Luster | Vitreous (Glassy) |
| Streak | White |
| Diaphaneity | Transparent |
| Specific gravity | 2.51 |
| Density | 2.51 |
| Optical properties | Uniaxial (+) |
| Refractive index | 1.511 to 1.532 |
| Birefringence | 0.021 |
| Pleochroism | Colorless to pink |
| References | [2][3][4][5][6] |
