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.