Franklinite
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Mineral NameFranklinite
Chemical Formula(Zn,Mn²⁺,Fe²⁺)(Fe³⁺,Mn³⁺)₂O₄
Mohs Hardness5.5
Streak Colorreddish brown
Cleavagenone
Fractureconchoidal to uneven
Specific Gravity5.07
Colorsblack, brownish-black, dark reddish-brown, reddish-orange
Transparencyopaque
Type LocalityFranklin and Sterling Hill, New Jersey, USA
Mineral GroupOxides
Usesminor ore of zinc, minor ore of manganese, collector's specimens
Associated Mineralszincite, willemite, calcite, rhodonite, andradite
Rarityuncommon
Description
A reddish-orange to dark reddish-brown fragment, appearing somewhat translucent under magnification, with angular or blocky forms.
Geological Context
Franklinite forms in highly metamorphosed zinc-manganese ore deposits, typically associated with marble or skarn, under high-temperature, low-pressure conditions.
