Enargite is a copper arsenic sulfosalt mineral with formula: Cu3AsS4. It takes its name from the Greek word enarge, "distinct." Enargite is a steel gray, blackish gray, to violet black mineral with metallic luster. It forms slender orthorhombic prisms as well as massive aggregates. It has a hardness of 3 and a specific gravity of 4.45.
This mineral is brittle and it has often small cavities that may be seen on surface of the stone.
From San Francisco vein, Junin Department, Peru.
Size: 11.4x11.4x6.3 mm.
Weight: 6.94 ct.