Jaszczakite
Jaszczakite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula [Bi₃S₃][AuS₂].
It crystallizes in the orthorhombic crystal system (space group Pmmn). It is a member of the Buckhornite structural group.
Key properties: Mohs hardness 2.5–3; specific gravity 7.237; Black streak; Metallic. Bireflectance: Weak luster.
IMA symbol Jzz, IMA status: approved, named in 2016.
From a mineralized breccia pipe hosted within calc-alkaline rocks.
It is found associated with Jonassonite, arsenopyrite, cosalite, pyrite, marcasite, sphalerite, chalcopyrite, gold, bismuth, bismuthinite, ikunolite, quartz.
The mineral was named to honor John A. Jaszczak (b. 1961), Professor of Physics at the Michigan Technological University, and Adjunct Curator at the A.E. Seaman Mineral Museum.