Paracostibite

paracostibite

costibite

nisbite

ullmannite

Images

Formula: CoSbS
Sulphide of cobalt and antimony, löllingite group, orthorhombic high-temperature paramorph of costibite, that is also orthorhombic
Crystal System: Orthorhombic
Specific gravity: 6.9 to 6.97 measured
Hardness: 7
Colour: White with a faint greyish tinge
Common impurities: Fe,Ni,As
Environments

Metamorphic environments
Hydrothermal environments

Localities

At the type locality, the Trout Bay Copper Mine, Mulcahy Township, Kenora District, Ontario, Canada, paracostibite was found in a drill core from a massive base-metal sulphide ore in a carbonatised chlorite-anthophyllite schist. The principal opaque minerals in the ore consist of coarse grains and inclusions of pyrrhotite, sphalerite and chalcopyrite. There are lesser amounts of galena, marcasite, arsenopyrite, cobaltite, pyrargyrite, paracostibite, gudmundite, stannite, silver-bearing tetrahedrite, antimonial silver, allargentum, ilmenite, breithauptite, cassiterite and nisbite.
Paracostibite was found in several sections as irregular and subhedral grains up to about 130 microns in size, in an assemblage of sphalerite, paracostibite, pyrargyrite, pyrrhotite, antimonial silver, galena and chalcopyrite. It was never found in close proximity to arsenopyrite or cobaltite but did occur in one section where these two minerals also occurred (CM 10.232-246, HOM ).

At the Gruvåsen and Getön mines, Persberg ore district, Filipstad, Värmland County, Sweden, costibite, paracostibite, nisbite and cobalt-bearing ullmannite are found associated together for the first time. The minerals were probably formed by remobilisation of cobalt from older sulphides by hydrothermal solutions during emplacement of younger granite (CM 18.165-171). Other associated minerals include chalcopyrite, pyrrhotite, galena, sphalerite and gersdorffite (HOM).

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