Formula: AgPbBi3S6
Sulphosalt, lillianite homologous series group, forms a series with lillianite, silver- and bismuth- bearing mineral
Crystal System: Orthorhombic
Specific gravity: 7.01 calculated
Hardness: 3½
Streak: Grey
Colour: Steel-grey
Common impurities: Sb

Hydrothermal environments

Gustavite is a rare mineral of hydrothermal origin that also occurs in pegmatites. Associated minerals include aikinite, bismuthinite, cosalite, pavonite, benjaminite, bismuth, chalcopyrite, tetrahedrite, pyrrhotite, stannite and arsenopyrite (HOM).


At the Tanco mine, Bernic Lake, Lac-du-Bonnet area, Manitoba, Canada, the pegmatite deposit is mined for tantalum oxide minerals, but it also contains refractory-grade spodumene and the world's largest known concentration of pollucite. Rare occurrences of sulphide minerals have been encountered, including gustavite, that occurs in grains up to 2 mm in size associated with aikinite-bismuthinite intergrowths, cosalite, native bismuth, chalcopyrite, tetrahedrite, pyrrhotite, stannite and arsenopyrite (CM 13.411-414).

At the Silver Bear mine, Camsell River area, Northwest Territories, Canada, the deposit is a silver-rich ore in which two distinct mineral assemblages, one sulphide and one arsenide, are evident. The sulphide assemblage consists mainly of pyrite, chalcopyrite, sphalerite, galena and tetrahedrite, whereas the arsenide assemblage, which is more complex, consists mainly of nickeline, safflorite, skutterudite, rammelsbergite, arsenopyrite, native silver, native bismuth, bismuthinite, matildite, gustavite, acanthite and a pavonite-type mineral. Gustavite is rare in the ore and occurs as inclusions (up to 200 microns) in the cores of arsenide rosettes associated with bismuthinite, matildite and the pavonite-type mineral (CM 13.411-414).

At the type locality, the Ivigtut mine, Arsuk Fjord, Sermersooq, Greenland, gustavite occurs as grains, tabular in form and sometimes slightly bent. Maximum grain size is 2 x 2 x 0.5 mm. Associated Minerals include galena and berryite (Mindat).

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