Montbrayite

montbrayite

tellurobismuthite

altaite

melonite

Images

Formula: (Au,Ag,Sb,Bi,Pb)23(Te,Sb,Bi,Pb)38
Tellurobismuthide
Specific gravity: 9.94
Hardness: 2½
Streak: White
Colour: Yellowish white, light yellow, tin white
Common impurities: Ag,Pb,Bi,S
Environments

Hydrothermal environments

Localities

At the type locality, the Robb-Montbray mine, Rouyn-Noranda TE, Abitibi-Témiscamingue, Quebec, Canada, montbrayite is abundant in some specimens. Freshly broken surfaces show coarsely crystallised aggregates of montbrayite, tellurobismuthite, altaite, melonite, gold, chalcopyrite and pyrite. In polished sections the following minerals are found in contact with montbrayite or enclosed within it: altaite, tellurobismuthite, petzite, gold, chalcopyrite, melonite and frohbergite. Altaite, with small amounts of gold and petzite, occurs in thin stringers cutting montbrayite. Tellurobismuthite with subordinate altaite and small patches of petzite forms inclusions irregularly distributed through montbrayite. Petzite occurs as irregular areas often surrounding and traversing patches of montbrayite. Subhedral crystals of melonite, with or without partial rims of petzite, occur in montbrayite. The chalcopyrite does not occur in the montbrayite itself but at the boundaries of altaite, tellurobismuthite, petzite and gold with montbrayite (AM 34.345-347). Other associated minerals include calaverite, sphalerite, chalcocite, covellite and marcasite (HOM).

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