Hydrated sulphate containing hydroxyl, copiapite group
Specific gravity: 2.08 to 2.17
Hardness: 2½ to 3
Streak: Pale yellow
Colour: Crystals are sulphur-yellow to orange, massive material is greenish-yellow to olive-green.
Solubility: Readily soluble in water
Common impurities: Cu,Ca,Al
Copiapite is a secondary sulphate formed typically by the weathering and
oxidation of pyrite in a wide range of rock types, preserved in arid climates and rarely associated
with fumarolic action (HOM). Associated minerals include melanterite,
butlerite and amarantite
(HOM, AM 58.314).
At the type locality, Copiapó Province, Atacama, Chile, copiapite occurs with melanterite, fibroferrite, alunogen, halotrichite and other sulphates (Dana).
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