Images
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.
At the Monte Arsiccio Mine, Sant'Anna di Stazzema, Stazzema, Lucca Province, Tuscany, Italy, coquimbite has
been found with römerite,
krausite and halotrichite
(Mindat photo).
Coquimbite from the Monte Arsiccio Mine -
Image
Back to Minerals