tetrahedrite

noun

1. a steel-gray or blackish mineral with a brilliant metallic luster, essentially copper and antimony sulfide, (Cu, Fe, Zn, Ag,)12 Sb4S13, an end member of a series of solid solutions into which arsenic enters to form tennantite: mined as an ore of copper and silver.

noun

1. a grey metallic mineral consisting of a sulphide of copper, iron, and antimony, often in the form of tetrahedral crystals: it is a source of copper. Formula: (Cu,Fe) 12 Sb 4 S 13