Enstatite

Physical Properties
Chemical formula	Mg₂Si₂O₄
Class	Inosilicate Double chains of linked tetrahedra
Crystal system	Orthorhombic
Habit	Massive Blocky Fibrous Lamellar Prismatic Acicular
Color	Gray, green
Hardness	5 to 6
Specific gravity	3.2 to 3.5
Cleavage	Two perfect prismatic {210}
Fracture	Uneven
Luster	Vitreous, pearly
Transparency	Translucent
Streak	White, gray
Optical Properties
PPL	Nearly colorless May display varying strengths of pink to green pleochroism
XPL	1^st order colors Parallel extinction Straight, parallel lines
δ	0.008
	after Perkins, 326-327

Enstatite In Hand Sample