Plancheite
| Plancheite | |
|---|---|
Plancheite and Malachite, Milpillas mine, Sonora, Mexico | |
| General | |
| Category | Inosilicate |
| Formula | Cu8Si8O22(OH)4•(H2O) |
| IMA symbol | Pch |
| Strunz classification | 9.DB.35 (10 ed) 8/F.05-10 (8 ed) |
| Dana classification | 66.2.1.1 |
| Crystal system | Orthorhombic |
| Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Space group | Orthorhombic Space group: Pcnb |
| Identification | |
| Formula mass | 1,171 g/mol |
| Color | Pale blue, light blue, dark green |
| Crystal habit | Acicular, Fibrous, or Radial |
| Cleavage | None observed |
| Mohs scale hardness | 5.5 to 6 |
| Luster | Vitreous to silky |
| Streak | Light blue |
| Diaphaneity | Translucent to opaque |
| Specific gravity | 3.6 to 3.8 |
| Optical properties | Biaxial (+) |
| Refractive index | Nx = 1.645, Ny = 1.660 Nz = 1.715 Nx = 1.697, Ny = 1.718, Nz = 1.741 |
| Pleochroism | X colorless or pale blue, Y colorless or blue, Z blue or dark blue |
| Other characteristics | Nonfluorescent, nonmagnetic, not radioactive |
| References | |
Plancheite is a hydrated copper silicate mineral with the formula Cu8Si8O22(OH)4•(H2O). It is closely related to shattuckite in structure and appearance, and the two minerals are often confused.