Forsterite
Color: various shades of green, from yellow-green to olive green to greenish black, also white, brown or black
Streak: Colorless
Luster: vitreous to greasy
Habit: crystals thick tabular, massive, compact or granular
Hardness: 7
Specific gravity: 3.28 to 4.32
Cleavage: 2; {010} and {100} imperfect
Tenacity: Brittle
Twinning: Common on {100}, contact, simple, repeated; on {001}, lamellar
Crystal system: orthorhombic
Crystal class: 2/m 2/m 2/m