Common Forms/Occurrences: In veins associated with other sulfide minerals Useful Identification Test: Decomposed by H2SO4 and by dilute HNO3 Chemical formula: PbS Crystal System: Forms cubes and octahedrons Colour: Silvery gray Streak: Gray to dark gray Lustre: Metallic (M) Cleavage: Good in 3 directions, so breaks into cubes Fracture: Subconchoidal or even; Brittle Hardness: 2.5 Hardness Search: two Specific Gravity: 7.5 - 7.6
