OLIVINE

Photo shows peridot, the gem variety of the mineral forsterite (Mg2SiO4),

which is a member of the olivine group.

Chemical Composition: (Mg, Fe)2SiO4

Hardness: 6.5-7.0

Color: olive green to yellowish-green

Specific Gravity: 3.2-4.3

Cleavage planes: none; conchoidal fracture

Crystal Structure: small grains

Luster: nonmetallic

Other Properties: significant component of igneous rocks