These samples of enargite are displayed in the Smithsonian Museum of Natural History. Enargite is an sulfide mineral of copper and arsenic with the composition Cu3AsS4. This sample is about 8X8 cm and is from Butte, Montana. The sample is described as enargite with pyrite.
Enargite with pyrite from Quiruvilca mine, La Libertad, Peru. The sample is about 12x30 cm. The black metallic crystal sprays are enargite, an ore of copper. They grew on limestone, with brassy pyrite crystals.