Franklinite

franklinite

hetaerolite

spinel

jacobsite

Images

Formula: ZnFe3+2O4
Multiple oxide, spinel subgroup
Specific gravity: 5.2
Hardness: 5½ to 6½
Streak: Reddish brown to black
Colour: Black
Solubility: Soluble in hydrochloric acid
Common impurities: Mn2+, Mn3+, Fe2+, Ti,Al,Ca
Environments:

Metamorphic environments

Franklinite occurs in a zinc-rich orebody of marine carbonate sediments, weathered and later metamorphosed at high temperature (Webmin HOM), associated with zincite, willemite, calcite, andradite, manganosite, rhodochrosite, gahnite, magnetite, rhodonite, hausmannite, hetaerolite, jacobsite, braunite, sarkinite, berzeliite and hematite (HOM).

At Franklin, New Jersey, USA, franklinite has been found here with hodgkinsonite and calcite (FM 38396).

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