Jarosite

sulphate

hydrothermal

Formula: KFe3+3(SO4)2(OH)6 sulphate, alunite group
Specific gravity: 2.9 to 3.3
Hardness: 3 to 4
Streak: Yellow
Colour: Ochre-yellow, brown to blackish brown
Solubility: Moderately soluble in hydrochloric acid
Environments:

Hydrothermal environments

Jarosite is a secondary mineral found in the oxidation zone of hypothermal (high temperature) veins and sulphide deposits, formed by weathering in arid climates.

Common impurities: Na,Ag,Pb

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