Kieserite | |
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General | |
Category | Sulfate minerals |
Formula (repeating unit) | MgSO4·H2O |
IMA symbol | Ksr[1] |
Strunz classification | 7.CB.05 |
Dana classification | 29.6.2.1 |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | C2/c |
Unit cell | a = 7.51 Å, b = 7.61 Å c = 6.92 Å; β = 116.17°; Z = 4 |
Identification | |
Color | Colorless, grayish-white or yellowish |
Crystal habit | Massive, granular; rarely as pyramidal crystals |
Twinning | Contact on {001}, polysynthetic about [110] |
Cleavage | {110} and {111} perfect |
Fracture | Uneven |
Tenacity | Fragile |
Mohs scale hardness | 3.5 |
Luster | Vitreous to dull |
Streak | White |
Diaphaneity | Transparent to translucent |
Specific gravity | 2.57 |
Optical properties | Biaxial (+) |
Refractive index | nα = 1.520 nβ = 1.533 nγ = 1.584 |
Birefringence | δ = 0.064 |
2V angle | 55° |
Dispersion | r > v, moderate |
Solubility | In water |
References | [2][3][4] |
Kieserite, or magnesium sulfate monohydrate, is a hydrous magnesium sulfate mineral with formula (MgSO4·H2O).
It has a vitreous luster and it is colorless, grayish-white or yellowish. Its hardness is 3.5 and crystallizes in the monoclinic crystal system. Gunningite is the zinc member of the kieserite group of minerals.[5]