Copiapite

minerals

melanterite

fibroferrite

Formula: Fe2+Fe3+4(SO4)6(OH)2.20H2O
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
Environments

Hydrothermal environments

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, alunogen, fibroferrite, halotrichite, botryogen, butlerite and amarantite (HOM, AM 58.314).

Localities

At the type locality, Copiapó Province, Atacama, Chile, copiapite occurs with melanterite, fibroferrite, alunogen, halotrichite and other sulphates (Dana).

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