Mckinstryit fotografiert im Museum für Naturkunde Berlin Fundort:Silver City in New Mexico (USA) — Photo: Oceancetaceen Alice Chodura · CC BY-SA 3.0
Mckinstryite
Mckinstryite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Ag₅Cu₃S₄.
It crystallizes in the orthorhombic crystal system (space group Pnma).
Key properties: specific gravity 6.61; Dark steel-gray. Anisotropism: Strong, in gray streak.
IMA symbol Mck, IMA status: approved, named in 1966.
Of hydrothermal or supergene origin; probably formed below 94.4 ° C, the upper stability limit for mckinstryite.
It is found associated with Silver, arsenopyrite, stromeyerite, actinolite, calcite (Foster mine, Canada); bornite, chalcocite, chalcopyrite, djurleite, digenite, tennantite.
In honor of Hugh Exton McKinstry (1896–1961), Professor of Geology at Harvard University, Cambridge, Massachusetts, USA.