Isometric (Cubic)
Tetrahedrite is a copper-antimony sulfosalt that forms the antimony end-member of an extensive solid-solution series with tennantite (As-end). It is the most abundant and widely distributed sulfosalt and a significant ore of copper, silver and antimony.
Occurrence in China
Tetrahedrite is widespread in Yunnan and Sichuan Cu-Pb-Zn-Ag deposits (Lanping, Gejiu) and in the Hunan W-Sn-Sb belt. Globally noted at Cornwall (UK), Bolivia and Peru.
Identification
Sharp tetrahedral crystal habit (when present) is the species’ namesake feature. Cubic system + dark steel-gray color + tetrahedron form distinguish it from galena (cubic crystals) and chalcopyrite (brassy yellow, tetragonal).
Collector Notes
Sharp, isolated tetrahedra perched on chalcopyrite or quartz are the most desirable form. Often Ag-rich varieties (freibergite) command extra interest from silver-mineral specialists.