Physical properties
Habit: dodecahedral, granular, crystalline, lamellar.
Color: red or black.
Luster: vitreous (i.e., glassy).
Streak: white.
Cleavage: none.
Parting: {110}.
Fracture: conchoidal.
Diaphaneity: transparent to translucent.
Chemical: soluble in HF.
Occurrence: ultrabasic igneous rocks.
