Home > American Minerals – January 11 > MS1990 Franklinite


Franklinite is a nominally a zinc iron oxide; most samples contain considerable but nonessential manganese. Berthier (1819) first analyzed the mineral; but it was Silliman (1820) who named the mineral for its occurrence at Franklin. Franklinite is a member of the spinel group, and as such typically forms octahedral crystals.

This is a loose mass of franklinite crystals, both solid and heavy, fortunately loose enough to show octahedral habit. The largest octahedra here reach 1.2 cm across. Some adhering calcite has been etched by acid. Minor red zincite is also present. This specimen was part of the Robert Trimingham and Ray McCammon collections, and carries their labels.

Price: $400

Item code: MS1990

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