Color: brownish, bright red, blood red, brownish red, steel gray, or iron black
Streak: brownish red
Hardness: 5–6
Specific gravity: 5.26
Cleavage: none
Fracture: uneven to subconchoidal
Luster: metallic to dull
Crystal form: trigonal/hexagonal
Transparency: opaque
Forms from hydrothermal fluid, sometimes replacing other minerals. May also form in igneous rocks.
For an explanation of the properties (in bold face), click here >>