Valleriite
| Valleriite | |
|---|---|
Cubanite (brass yellow), maucherite (dark gray) and valleriite (dark bronze), mainly | |
| General | |
| Category | Sulfide mineral |
| Formula | (Fe2+,Cu)4(Mg,Al)3S4(OH,O)6 |
| Strunz classification | 2.FD.30 |
| Dana classification | 2.14.1.1 |
| Crystal system | Trigonal |
| Crystal class | Hexagonal scalenohedral (3m) H-M symbol: (3 2/m) |
| Space group | R3m |
| Unit cell | a = 3.79, c = 34.1 [Å]; Z = 2 |
| Identification | |
| Color | Bronze-yellow, gray |
| Crystal habit | Massive, nodular, encrustations, thin splintery |
| Cleavage | Excellent on {0001} |
| Mohs scale hardness | 1–1.5 |
| Luster | Metallic |
| Streak | Black |
| Diaphaneity | Opaque |
| Specific gravity | 3.14 (measured) |
| Pleochroism | Strong; pale yellow to deep brown |
| References | |
Valleriite is an uncommon sulfide mineral (hydroxysulfide) of iron and copper with formula: 4(Fe,Cu)S·3(Mg,Al)(OH)2 or (Fe2+,Cu)4(Mg,Al)3S4(OH,O)6. It is an opaque, soft, bronze-yellow to brown mineral which occurs as nodules or encrustations.