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Formula: AlFe3+3(SO4)6(H2O)12.6H2O
Hydrated sulphate, coquimbite group,
paramorph of
paracoquimbite and epitaxial on it
Crystal System: Trigonal
Specific gravity: 2.11 measured, 2.12 calculated
Hardness: 2½
Streak: White
Colour: Light violet to purple, greenish white, bluish white, yellowish white, brownish white
Luminescence: Not fluorescent under UV
Solubility: Soluble in cold water and in acids
Common impurities: Al
Environments
Hydrothermal environments
Fumeroles rarely
Coquimbite typically is a secondary mineral in the oxidised
portions of weathering iron sulphide deposits in arid regions; rarely in fumeroles. Associated minerals include
copiapite, paracoquimbite,
voltaite, szomolnokite and
römerite
(HOM).
Localities
The type locality is Coquimbo, Chile.
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