Goslarite | |
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General | |
Category | Sulfate mineral |
Formula (repeating unit) | ZnSO4·7H2O |
IMA symbol | Gos[1] |
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 | [2][3][4][5] |
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).