Enstatite

Formula:   Mg₂Si₂O₆

Origin of name:   From Greek for opponent

Crystal system:   Orthorhombic

Crystal class:   2/m 2/m 2/m

Twinning:

Unit cell: 

Colour:  Colourless, yellow or greenish white, gray, olive-green, brown

Diaphaneity:  Transparent to nearly opaque

Luster:   Vitreous to pearly

Habit:   Crystals prismatic; massive, lamellar, fibrous

Hardness:   5 to 6

Specific gravity:   3.21 to 3.43

Cleavage:   3; {210} good, {100} and {010} parting

Tenacity: 

Streak:   Colourless, grayish

Synonyms/varieties:

Comments:   Series with ferrosilite; dimorphous with clinoenstatite