Putzite
Putzite is an IMA-recognized mineral species in the sulfide class, with the chemical formula (Cu,Ag)₈GeS₆.
It crystallizes in the cubic crystal system (space group F-43m). It is a member of the Argyrodite structural group.
Key properties: Mohs hardness 3–3.5; specific gravity 5.778; Black streak; Metallic luster.
IMA symbol Pzi, IMA status: approved, named in 2002.
Fills cavities and vugs in bornite-chalcocite ore in association with andesitic rocks which host porphyry Cu-Au and epithermal vein-type mineral deposits.
It is found associated with Catamarcaite, hübnerite, Ge-stannoidite, luzonite, sphalerite, tennantite, thalcusite, wittichenite, chalcocite, bornite.
The mineral was named to honor Hubert Putz (b. 1973), who discovered the first specimens and who has made a significant contribution to the mineralogy of Ge in the Capillitas deposit.