Maldonite Locality: Eagle Hawk Union Mine, Maldon, Victoria (Australia) Exposed in the Mineralogical Museum of University Bonn, Germany — Photo: Ra'ike · CC BY-SA 3.0
Maldonite
Maldonite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Au₂Bi.
It crystallizes in the cubic crystal system (space group Fd3m).
Key properties: Mohs hardness 1.5–2; specific gravity 15.46; Metallic. R: (400) 48.3, (420) 49.0, (440) 50.2, (460) 51.5, (480) 53.2, (500) 54.9, (520) 56.6, (540) 58.0 luster.
IMA symbol Mdo, grandfathered status — known before the IMA’s founding, named in 1869.
Formed below 373 ° C, under hydrothermal conditions in gold-quartz veins and stockworks, and calc-silicate skarns.
It is found associated with Gold, bismuth, bismuthinite, joséite, arsenopyrite, löllingite, pyrite, pyrrhotite, chalcopyrite, cubanite, scheelite, apatite, siderite, calcite, quartz.
The name is derived from the locality at Maldon, Australia.