Augite

Augite
General
Category	Silicate mineral
Formula (repeating unit)	(Ca,Mg,Fe)SiO3
Identification
Color	Pale brown to purplish or greenish brown, also dark grey sometimes
Crystal system	Monoclinic
Cleavage	{110} good
Fracture	uneven
Mohs scale hardness	5 to 6.5
Luster	Vitreous
Streak	Greenish-white
Specific gravity	3.19 - 3.56
Refractive index	α = 1.671 - 1.735, β = 1.672 - 1.741, γ = 1.703 - 1.774

Augite is a mineral. The mineral's name comes from the Greek word augites, meaning "brightness". However, augites only look shiny some of the time. Most augites have a dull (dark green, brown or black) color. Augite is a pyroxene.