Chromite

Physical Properties
Chemical formula FeCr2O4
Class Oxide
Crystal system Cubic
Habit Massive
Granular
Rare euhedral crystals
are octahedral
Color Black
Brownish black
Hardness 5.5
Specific gravity 5.10
Cleavage None
Fracture Conchoidal
Luster Metallic
Transparency Subtranslucent
Opaque
Streak Brown
Dark brown
after Perkins, 376

Chromite in Hand Sample

Four views of chromite in Stillwater Complex chromite olivine cumulate:

One
Two
Three
Four

Further Reading

Chromite at webmineral.com
Chromite at mindat.org