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(CLINOPYROXENES*) (Ca,Na,Mg,Fe,Mn,Al,Ti)2[(Si,Al)2O6]
Crystal system: Monoclinic
Refractive index: 1.662-1.761
Birefringence: 0.018-0.033
Cleavage: 2 good, 87 o
Twinning: simple, multiple common
Colour in PPL: colourless, pale brown, pale green
Pleochroism: strongly coloured varieties may show weak to moderate
Relief: high
Distinction: augite from diopside by lower birefringence and higher refractive indices
Occurrence: typical pyroxene of basalts, gabbros, etc, also high-grade metamorphic rocks
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