Kieserite

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Kieserite
Kieseriet (Kieserite).jpg
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]

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[edit]

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[edit]

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[edit]

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]

Crystal structure of kieserite

See also[edit]

References[edit]

  1. ^ Kieserite data on Webmineral
  2. ^ Kieserite on Mindat.org
  3. ^ a b Kieserite in the Handbook of Mineralogy
  4. ^ Kieserite group on Mindat
  5. ^ Industrial Inorganic Chemistry, Karl Heinz Büchel, Hans-Heinrich Moretto, Dietmar Werner, John Wiley & Sons, 2nd edition, 2000, ISBN 9783527613335