Orthorhombic
Enargite is a copper-arsenic sulfosalt that serves as a major Cu-As ore mineral in high-sulfidation epithermal and porphyry-related deposits. It typically forms blocky to tabular dark-gray crystals with characteristic striated faces.
Occurrence
Classic Andean high-sulfidation deposits: Cerro de Pasco and Quiruvilca (Peru), El Indio (Chile), Butte (Montana). In China, minor occurrences in Yunnan Cu-As deposits but rarely in collector quality.
Identification
Striated orthorhombic prisms + iron-black color + perfect prismatic cleavage. Distinguish from tetrahedrite (cubic, no cleavage) and bournonite (no perfect cleavage, different chemistry).
Collector Notes
Quiruvilca enargite tabular crystals on pyrite are the genre standard. Important for chemistry collectors completing the Cu-As-Sb sulfosalt system alongside tetrahedrite-tennantite-bournonite.