The new mineral occurs within a cavity in a massive
tennantite sample (4 X 5 X 7 cm) from the Tsumeb mine at Tsumeb, Namibia.
The pseudomorphs are intergrown with quartz prisms,
tennantite crystals to 1 cm, and black sphalerite crystals to 3 cm covered by tiny
tennantite tetrahedrons.
Beautiful crystals of chalcopyrite are rather rare in the deposit, despite the production of 2,000 tonnes/year of copper concentrates at Trepca (copper in the ore is contained in chalcopyrite, pyrrhotite, tetrahedrite,
tennantite, bournonite, bornite and enargite).
Any of the rarer species from Silvermines such as jordanite, proustite,
tennantite etc.
There, it is associated with cinnabar, native mercury, sphalerite,
tennantite, chalcopyrite, polydymite and pyrite.
Tennantite (Cu,Ag,Fe,Zn)[.sub.12][As.sub.4][S.sub.13] (OV)
Occurrence: In the oxidized zone in a "nest" consisting of galena, tetrahedrite and
tennantite in a quartz vein.
The Smithsonian filled a case with fine Tsumeb minerals including leadhillite, anglesite,
tennantite, azurite, smithsonite and other collector species.
We have only observed the primary species chalcopyrite and
tennantite ([[Cu.sub.9.48][Fe.sub.1.50][Ag.sub.0.92] [Zn.sub.0.32]]-[[As.sub.3.56][Sb.sub.0.25][P.sub.0.05]][S.sub.13]) for a total of 99.48 percent of the weight, in a La Atalaya specimen.
Large
tennantite (X-ray verified) crystals to 5 cm were found in 2002, some of them partially covered by green scorodite.
Freibergite is a rare member of the tetrahedrite group in which silver predominates over copper and iron in the cation sites; good crystals have always been rare, and must in any case be analytically verified as freibergite, as they cannot be visually distinguished from tetrahedrite or
tennantite. The new freibergites from a discovery late last summer in the famous Herja mine, Maramures, Rommia have been so verified, and about 50 small-thumbnail-sized specimens were brought to Tucson this year by Ross billie of North Star Minerals.
World-class-caliber specimens of many species have been found at Peruvian sites in the last few decades, including pyrite, sphalerite, galena, chalcopyrite, tetrahedrite,
tennantite, hubnerite, fluorite, rhodochrosite, gypsum, atacamite, quartz, epidote, rhodonite and silver.