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

Hydrothermal environments

Maldonite occurs in gold - bismuth - telluride - sulphide assemblages (AJM 15.25-38).


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).

Back to Minerals