Goslarite
| Goslarite | |
|---|---|
Goslarite on display at the Museo Nacional de Ciencias Naturales | |
| General | |
| Category | Sulfate mineral |
| Formula | ZnSO4·7H2O |
| IMA symbol | Gos |
| Strunz classification | 7.CB.40 |
| Crystal system | Orthorhombic |
| Crystal class | Disphenoidal (222) (same H-M symbol) |
| Space group | P212121 |
| Unit cell | a = 11.8176 Å, b = 12.0755 Å c = 6.827 Å, Z = 4 |
| Identification | |
| Formula mass | 287.56 g/mol |
| Color | Colorless, pinkish, white, greenish, green, blue, green blue, bluish and brownish |
| Crystal habit | Acicular, massive, stalactitic |
| Cleavage | {010} perfect |
| Fracture | Conchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 2.0–2.5 |
| Luster | Vitreous (glassy) |
| Streak | White |
| Specific gravity | 1.96 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.447 - 1.463 nβ = 1.475 - 1.480 nγ = 1.470 - 1.485 |
| Birefringence | δ = 0.0220–0.0230 |
| Pleochroism | none |
| 2V angle | 46° |
| References | |
Goslarite is a hydrated zinc sulfate mineral (ZnSO4 · 7 H2O) which was first found in the Rammelsberg mine, Goslar, Harz, Germany. It was described in 1847. Goslarite belongs to the epsomite group which also includes epsomite (MgSO4 · 7 H2O) and morenosite (NiSO4 · 7 H2O). Goslarite is an unstable mineral at the surface and will dehydrate to other minerals like bianchite (ZnSO4 · 6 H2O), boyleite (ZnSO4 · 4 H2O) and gunningite (ZnSO4 · H2O).