Polydymite

polydymite

pyrrhotite

gersdorffite

ullmannite

Images

Formula: Ni2+Ni3+2S4
Sulphide, linnaeite subgroup, thiospinel group, spinel supergroup, forms a series with linnaeite, nickel-bearing mineral
Specific gravity: 4.5 to 4.8
Hardness: 4½ to 5½
Streak: Black-grey
Colour: Violet-grey, copper-red, light grey, steel-grey
Common impurities: Fe,Co
Environments

Hydrothermal environments

Polydymite occurs in hydrothermal veins associated with chalcopyrite, pyrrhotite, pyrite, millerite, gersdorffite, ullmannite, sphalerite, galena, bismuthinite, quartz and siderite (HOM).

Localities

The type locality is the Grüneau Mine, Schutzbach, Daaden-Herdorf, Altenkirchen District, Rhineland-Palatinate, Germany.

At Hamilton, Hancock county, Illinois, USA, polydymite has been confirmed as inclusions in calcite (Minrec 36.5.427).

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