Siegenite

siegenite

millerite

gersdorffite

ullmannite

Images

Formula: CoNi2S4
Sulphide, linnaeite subgroup, thiospinel group, spinel supergroup, forms a series with violarite and with linnaeite, cobalt- and nickel- bearing mineral
Crystal System: Isometric
Specific gravity: 4.5 to 4.8 measured, 4.83 calculated
Hardness: 4½ to 5½
Streak: Greyish black
Colour: Light to steel-grey, violet-grey (tarnished)
Common impurities: Se,Cu,Fe
Environments

Hydrothermal environments

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

Localities

At the Langis mine, Casey Township, Cobalt Area, Cobalt-Gowganda region, Timiskaming District, Ontario, Canada, most of the siegenite in this occurrence is intimately intergrown with cobaltpentlandite, although some is also present as separate grains (CM 9.5.597–616).

The type locality is the Stahlberg mine, Müsen, Hilchenbach, Siegen-Wittgenstein, Arnsberg, North Rhine-Westphalia, Germany.
Siegenite from the Stahlberg mine - Image

At the Emma-Hendrik coal dump, Brunssum, Limburg, Netherlands, siegenite has been found on ankerite (Mindat photo).
Siegenite from the Emma-Hendrik coal dump - Image

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