Jonassonite

jonassonite

ikunolite

bismuthinite

joseite

Images

Formula: Au(Bi,Pb)5S4
Sulphosalt, bismuth-bearing mineral
Crystal System: Monoclinic
Specific gravity: 8.64 calculated
Hardness: 2½ to 3
Streak: Black
Colour: Tin-white
Environments

Hydrothermal environments

Jonassonite is a relatively new mineral, approved in 2004, and occurring in sulfide/arsenide/selenide veins (Mindat).

Localities

At the North British mine, Maldon, Mount Alexander Shire, Victoria, Australia, jonassonite occurs as microscopic grains with other bismuth-tellurium phases in millimetre-sized patches in seamy quartz, associated with native bismuth and joséite-B (AJM 15.32-33).

At the type locality, Nagybörzsöny, Szob District, Pest County, Hungary, jonassonite was detected in old mining dumps of the abandoned deposit. The mineralisation is hosted by calc-alkaline volcanic rocks and occurs as a stockwork in a propylitised dacite breccia pipe. The assemblage of metallic minerals with which jonassonite is associated consists of arsenopyrite, pyrite, marcasite, pyrrhotite, sphalerite, chalcopyrite, native gold, native bismuth, bismuthinite, ikunolite, cosalite, lillianite and possibly cannizzarite.
Jonassonite occurs as anhedral grains of up to 500 × 150 μm, and contains inclusions of native bismuth, ikunolite and bismuthinite (CM 44.1127-1136).

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