Mineral Species: Goldfieldite

Chemical Formula: Cu12(Te,Sb,As)4S13

Chemical Name: Copper Tellurium Antimony Arsenic Sulphide

Mineral Class: Sulphide

Mineral Notes: Goldfieldite forms in epithermal gold-bearing veins and less commonly in porphyry copper and volcanogenic massive sulfide deposits. It belongs to the tetrahedrite group. The mineral is named after the type locality, Goldfield, Nevada, USA.

Description: Granular Goldfieldite in grey Quartz. Magnification shows some crystalline form but these flattened crystals are fused into a solid coating, which occurs in several places on the matrix. The mineral has a very deep black colour and a very strong metallic luster.

Location: Goldberg Mine, Creede, San Juan Co, Colorado, USA.