Blödite

Sulfate mineral

(repeating unit)Na₂Mg(SO₄)₂·4H₂OIMA symbolBlö^[1]Strunz classification7.CC.50Crystal systemMonoclinicCrystal classPrismatic (2/m)
(same H-M symbol)Space groupP2₁/aUnit cella = 11.04 Å, b = 8.15 Å,
c = 5.49 Å; β = 100.41°; Z = 2IdentificationColorColorless, yellow, may be dark gray, bluish green, or reddish due to inclusionsCrystal habitPrismatic to equant crystals, granular, massiveFractureConchoidalTenacityBrittleMohs scale hardness2.5–3LusterVitreousSpecific gravity2.23Optical propertiesBiaxial (−)Refractive indexn_α = 1.483, n_β = 1.486, n_γ = 1.487Birefringenceδ = 0.0042V 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.

References

^ 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.
^ Handbook of Mineralogy
^ ^a ^b Blödite on Mindat.org
^ ^a ^b Blödite data on Webmineral