Augite
Crystal sys.: monoclinic
Color: black, greenish black, dark brown to violet
colorless.
SG: 3.2 - 3.5
Hardness: 5 - 6
Comments: common mineral in plutonic rocks, volcanic
rocks, high temperature metamorphic rocks.
Altered by intergrowths of hornblende
(uralite), chlorite, epidote, and calcite.
Information (including a thin section) on augite.