Augite
Augite is a
mafic mineral described chemically as (Ca, Na)(Mg, Fe, Al)(Al, Si)
2O
6 or
calcium sodium magnesium iron aluminium silicate. Structurally, it is a solid solution of the
pyroxene group which also contains diopside and hedenbergite. The
crystals are monoclinic and prismatic. It is found in igneous rocks such as gabbros and basalts, and in metamorphic rocks from hydrothermal vents. Occasional specimens have a shiny appearance that give rise to the mineral's name, which is from the Greek
augites, meaning "brightness", although ordinary specimens have a dull (dark green, brown or black) finish.
Data