Franklinite

oxide

Tsumeb

Formula: ZnFe3+2O4
Multiple oxide, spinel group
Specific gravity: 5.2
Hardness: 5½ to 6½
Streak: Reddish brown to black
Colour: Black
Solubility: Soluble in hydrochloric acid
Environments:

Metamorphic environments

Franklinite occurs in a zinc-rich orebody of marine carbonate sediments, weathered and later metamorphosed at high temperature. Associated with zincite, willemite, calcite, andradite, manganosite, rhodochrosite, gahnite, magnetite, rhodonite, hausmannite, hetaerolite, jacobsite, braunite, sarkinite, berzeliite and hematite.
Common impurities: Mn2+, Mn3+, Fe2+, Ti,Al,Ca

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