group pyroxene
system orthorhombic
formula (Mg,Fe)2Si2O6
optic biaxial neg / pos
Too-Vee 50 - 132¡
relief.1 moderate to high pos
min. index 1.649 / 1.788
color colorless
pleochroism yes
birefringence.1 0.007 - 0.020
cleavage yes parallel to {210}
intersect at 88 deg.
elongation yes
extinction parallel
angle 0¡
alteration serpentine, talc, or fine-grained amphibole
habit.1 prismatic, columnar, tabular
occurence igneous (ultramafic, mafic), metamorphic (high grade, contact)
TwoV 1 2
relief 2 3
pleochroism.2 pink, green
birefringence 1 3 4 5 6 7 8
cleavage.2 {210} typical pyroxene cleavage at 88¡