Galena
Chemical Formula	PbS
Species	Sulfides
Crystal System	Isometric
Mohs Scale	2
Specific Gravity	7.2-7.6
Color	Lead gray and silvery
Streak	Lead gray
Luster	Metallic, Dull
Diaphaneity	Opaque
Cleavage	Perfect
Fracture	Sub-Conchoidal
Crystal Habit：Cubes and octahedra, tabular and sometimes skeletal crystals