Point Group
hexoctahedral - 4/m 3 2/m
Habit
dodecahedron, granular, Octahedron, Cube
Formation
(1) Magmatic, as an accessory mineral in mafic to ultramafic rocks, as well as through fractional crystallization from aluminum-rich melts.
(2) Metamorphic, formed by contact or regional metamorphism in Al-rich sediments (metapelites) or impure limestones (skarns) under high temperatures.
Twinning
Contact twins after {111} -Spinel law
