Tungstite
| Tungstite | |
|---|---|
 Bright yellow tungstite on ferberite | |
| General | |
| Category | Mineral |
| Formula (repeating unit) | WO3·H2O |
| Strunz classification | 4.FJ.10 |
| Crystal system | Orthorhombic |
| Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Space group | Pmnb |
| Identification | |
| Formula mass | 249.86 g/mol |
| Color | Yellow, yellowish green/orange |
| Crystal habit | Earthy, pulverulent |
| Cleavage | Perfect along [001], imperfect along [110] |
| Mohs scale hardness | 2.5 |
| Luster | Resinous, pearly |
| Streak | Yellow |
| Diaphaneity | Transparent |
| Specific gravity | 5.517 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 2.090, nβ = 2.240, nγ = 2.260 |
| Birefringence | δ = 0.170 |
| Dispersion | r < v (strong) |
Tungstite is a hydrous tungsten oxide mineral with formula: WO3·H2O. It is a secondary mineral formed by the weathering of other tungsten containing minerals. It crystallizes in the orthorhombic system in translucent yellow to yellow green masses. It is clay-like with Mohs hardness of 2.5 and a specific gravity of 5.5.
It was first described in 1868 for an occurrence near Trumbull, Connecticut at the Hubbard Tungsten Mine at Long Hill.
References
Wikimedia Commons has media related to Tungstite.
