Sweet Home Mine

    Alma Park County

    Colorado, USA

Tetrahedrite gets its name from the distinct tetrahedron shaped cubic crystals it forms, in a steel gray to black metallic coloring. It was first described in Freiberg, Saxony, Germany, and was historically an important ore of copper and silver.

Tetrahedrite is an unusual mineral that is part of a solid solution series. A solid solution series occurs in nature when one element within a mineral is being replaced by another mineral over time until it changes the mineral type entirely. It occurs on a spectrum, with a different mineral on each end and in-between there are various states. Tetrahedrite is Copper Antimony Sulfide or Cu12Sb4S13. In the solid solution series of Tetrahedrite, the mineral Antimony is being replaced by Arsenic.

At the other end of the spectrum, is the rare mineral Tennantite (Cu12As4S13, Copper Arsenic Sulfide). The two minerals share the same crystal structure but they differ in the percentage of arsenic and antimony. Antimony rich crystals are Tetrahedrite while arsenic specimens are Tennantite.