Formula: ZnMn3+2O4
Multiple oxide, spinel group, forms a series with hausmannite
Specific gravity: 5.18
Hardness: 6
Streak: Dark brown
Colour: Black, reddish-black

Hydrothermal environments

Hetaerolite is a secondary mineral mainly found in hydrothermal ore deposits (Webmin), associated with franklinite, chalcophanite, hodgkinsonite, willemite, hemimorphite, manganite, romanèchite and calcite (Webmin, HOM).


At the Rodna Base Metal Ore Deposit, Rumania, hetaerolite is a productof weathering of manganese-bearing zinc ore. The Rodna deposit consists of metasomatic ore-bodies in metasomatic limestone and of injections in andesitic explosion-breccia. The ores consist predominantly of pyrite, sphalerite, pyrrhotite and galena. Hetaerolite was found in cavities within the crystalline limestone where it occurs in a matrix of limonitic ochre together with fragments of galena crystals, which have been partially coated by cerussite (AM 58.1065-1068).

At the type locality, the Passaic pit, Sterling Hill, Ogdensburg, Franklin Mining District, Sussex county, New Jersey, USA, hetaerolite is associated with calcite, willemite, manganosite, chalcophanite, gahnite and zincite (Dana). Hetaerolite as a lamellar exsolution growth in franklinite from Franklin has been found in four occurrences, in immediate association with manganosite and zincite, with willemite and rhodochrosite, with zincite and willemite and with tephroite and zincite (AM 50.1672).

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