Mineral, PbS; sp. gr. 7.4–7.6; hardness 2.5; cubic; lead-grey; lead-grey streak; metallic lustre; crystals cubes or octahedra, and often octahedral twins; cleavage perfect cubic {100}; widely distributed in hydrothermal veins and syngenetic exhalative deposits and as a replacement in limestones and dolomitic rocks, associated in veins with sphalerite, pyrite, chalcopyrite, barite, quartz, fluorite, and calcite.