Formula: Au2Bi
Alloy, copper group
Specific gravity: 15.46
Hardness: 1½ to 2
Colour: Silver white with pink tint, tarnishes to black
Stability: Thermodynamically unstable below ~116°C, but is found in a metastable state in nature (Mindat).
Common impurities: Ag
Environments
Maldonite occurs in gold - bismuth -
telluride - sulphide assemblages
(AJM 15.25-38).
Localities
At the type locality, Nuggety Reef, Maldon, Mount Alexander Shire, Victoria, the country rocks hosting the
quartz reefs in the gold field consist of
quartzite and hornfels with
occasional calc-silicate rocks and
skarn. The sequence of mineralisation is within the
biotite - cordierite -
K-feldspar zone of a contact
aureole surrounding granite.
Assemblages of native bismuth, gold, maldonite,
joséite and bismuthinite are dominated by
gold and native bismuth; other minerals found in the
assemblages include jonassonite, aurostibite and
hedleyite. The maldonite occurs as blebs up to 2 mm across surrounded by an irregular
fringe of intergrowths of gold and bismuth
(AJM 15.25-38).
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