Kieserite
| Kieserite | |
|---|---|
|
Kieserite | |
| General | |
| Category | Sulfate minerals |
| Formula (repeating unit) | MgSO4·H2O |
| Strunz classification | 07.CB.05 |
| Dana classification | 29.6.2.1 |
| Crystal symmetry |
Monoclinic prismatic H-M symbol: (2/m) Space group: C2/c |
| Unit cell | a = 7.51 Å, b = 7.61 Å, c = 6.92 Å; β = 116.17° |
| Identification | |
| Color | Colorless, grayish-white or yellowish |
| Crystal habit | Massive, granular; rarely as pyramidal crystals |
| Crystal system | Monoclinic |
| 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 | [1][2][3] |
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Kieserite is the magnesium sulfate mineral (MgSO4·H2O) and is named after Dietrich Georg von Kieser (Jena, Germany 1862). 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.[4]
Occurrence
Kieserite commonly occurs in marine evaporites and rarely in volcanic environments as a sublimate. It occurs in association with halite, carnallite, polyhalite, anhydrite, boracite, sulfoborite, leonite, epsomite and celestine.[3]
Mars
In early 2005, Mars Express, a European Space Agency orbiter, discovered evidence of kieserite in patches of Valles Marineris (the largest canyon on Mars), along with gypsum and polyhydrated sulfates. This is direct evidence of Mars's watery past and augments similar discoveries made by the Mars Exploration Rover Opportunity in 2004.
Uses
It is used in the production of Epsom salt and as a fertiliser, the overall global annual usage in agriculture in the mid 1970s was 2.3 million tons.[5]
See also
References
- ↑ Kieserite data on Webmineral
- ↑ Kieserite on Mindat.org
- ↑ 3.0 3.1 Kieserite in the Handbook of Mineralogy
- ↑ Kieserite group on Mindat
- ↑ Industrial Inorganic Chemistry, Karl Heinz Büchel, Hans-Heinrich Moretto, Dietmar Werner, John Wiley & Sons, 2nd edition, 2000, ISBN 9783527613335