Tsumoite

minerals

tetradymite

bismuthinite

cosalite

Images
Formula: BiTe
Telluride, tetradymite group
Crystal System: Trigonal
Specific gravity: 8.16 measured, 8.23 calculated
Hardness: 2½ to 3
Streak: Steel-grey
Colour: Silver-white
Common impurities: Pb
Environments

Metamorphic environments

Tsumoite occurs in massive nickelcopperplatinum group element deposits and in copperzinclead deposits. Associated minerals include pentlandite, chalcopyrite, pyrrhotite, sperrylite, parkerite, maucherite, michenerite, tetradymite, pilsenite, cosalite, altaite, bismuthinite and galena (HOM).

Localities

At the type locality, the Tsumo mine, Masuda City, Shimane Prefecture, Japan, tsumoite occurs as irregular aggregates to 1 cm in a clinopyroxene-garnet-quartz skarn. Associated minerals include tetradymite, galena, cosalite and bismuthinite (AM 63.1162-1165, Mindat).

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