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Blödite

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Blödite
Doubly terminated blödite crystal from Soda Lake, San Luis Obispo County, California (size: 7.0 × 4.8 × 1.9 cm)
General
CategorySulfate minerals
Formula
(repeating unit)
Na2Mg(SO4)2·4H2O
IMA symbolBlö[1]
Strunz classification7.CC.50
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/a
Unit cella = 11.04 Å, b = 8.15 Å,
c = 5.49 Å; β = 100.41°; Z = 2
Identification
ColorColorless, yellow, may be dark gray, bluish green, or reddish due to inclusions
Crystal habitPrismatic to equant crystals, granular, massive
FractureConchoidal
TenacityBrittle
Mohs scale hardness2.5–3
LusterVitreous
Specific gravity2.23
Optical propertiesBiaxial (−)
Refractive indexnα = 1.483, nβ = 1.486, nγ = 1.487
Birefringenceδ = 0.004
2V angle71° (measured)
References[2][3][4]

Blödite or bloedite is a hydrated sodium magnesium sulfate mineral with the formula Na2Mg(SO4)2·4H2O. The mineral is clear to yellow in color often darkened by inclusions and forms monoclinic crystals.

Blödite was first described in 1821 for an occurrence in a salt deposit in Ischler Salzberg, Bad Ischl, Gmunden, Austria and named for German mineralogist and chemist Karl August Blöde (1773–1820).[3][4]

It is found worldwide in evaporitic sedimentary environments such as the Great Salt Lake, Utah.

See also

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References

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  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Handbook of Mineralogy
  3. ^ a b Blödite on Mindat.org
  4. ^ a b Blödite data on Webmineral
Crystal from Soda Lake (size: 2.9 × 2.2 × 1.4 cm)