Jarosite

Jarosite
Jarosite on quartz from the Arabia District, Pershing County, Nevada
General
CategorySulfate minerals
Formula
(repeating unit)
KFe3(SO4)2(OH)6
IMA symbolJrs[1]
Strunz classification7.BC.10
Dana classification30.2.5.1
Crystal systemTrigonal
Crystal classRhombohedral (3m)
H-M symbol: (3m)
Space groupR3m
Unit cella = 7.304 Å, c = 17.268 Å; Z = 3
Identification
Formula mass500.8 g/mol
ColorAmber yellow or dark brown
Crystal habitCrystals are usually pseudocubic or tabular, also as granular crusts, nodules, fibrous masses or concretionary.
CleavageDistinct on {0001}
FractureUneven to conchoidal
TenacityBrittle
Mohs scale hardness2.5–3.5
LusterSubadamantine to vitreous, resinous on fractures
Streaklight yellow
DiaphaneityTransparent to translucent
Specific gravity2.9 to 3.3
Optical propertiesUniaxial (−), usually anomalously biaxial with very small 2V
Refractive indexnω = 1.815 to 1.820; nε = 1.713 to 1.715
Birefringence0.102 to 0.105
PleochroismE colorless, very pale yellow, or pale greenish yellow, O deep golden yellow or reddish brown
SolubilityInsoluble in water. Soluble in HCl.
Other characteristicsStrongly pyroelectric. Non-fluorescent. Barely detectable radioactivity
References[2][3][4]

Jarosite is a basic hydrous sulfate of potassium and ferric iron (Fe-III) with a chemical formula of KFe3(SO4)2(OH)6. This sulfate mineral is formed in ore deposits by the oxidation of iron sulfides. Jarosite is often produced as a byproduct during the purification and refining of zinc and is also commonly associated with acid mine drainage and acid sulfate soil environments.

  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. ^ Gaines et al (1997) Dana's New Mineralogy Eighth Edition, Wiley
  3. ^ "Jarosite".
  4. ^ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Jarosite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 14 March 2022.

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