Chromite
ID: 20
Chromite
Chemical Formula
FeCr₂O₄
Hardness (Mohs)
5.5
Crystal System
Isometric
Streak
Brownish-black
Luster
Metallic to submetallic (often dull in masses)
Diaphaneity
Opaque
Color
Black to brownish-black
Crystal Habit / Mode of Occurrence
Isometric - Hexoctahedral; commonly octahedral crystals (often very small), frequently massive, granular, disseminated grains.
Fun Facts
Nearly all the world's chromite comes from layered mafic and ultramafic intrusions, formed as early-crystallizing minerals settling out of magma. Common Uses: Primary ore of chromium (used in stainless steel, plating, pigments, chemicals), refractory material.