Crystal Form: Tetrahedron

Habit: Granular or massive

Hardness: 3-4.5

Cleavage/Fracture: No cleavages; fracture: Subconchoidal to uneven

Luster: Metallic

Color: Gray to black

Streak: Brown to black

Specific Gravity: 4.6-5.1

Other Characteristics:

　　　(1) Crystal twinning

　　　(2) Opaque