Diopside

1. ppl w/ OPX

group                                   inosilicate
system                                  monoclinic
formula                                 CaMgSi2O6
optic                                   biaxial pos
Too-Vee                                 25 -70¡
relief.1                                high pos
min. index                              1.664  / 1.771
color                                   colorless, gray, green, brown 
pleochroism                             yes 
birefringence.1                         0.018 - 0.034
cleavage                                yes  
elongation                              no 
extinction                              inclined, symmetrical
angle                                   35 - 50¡
alteration                              uralite, serpentine, chlorite, biotite, carbonates
habit.1                                 prismatic, columnar, tabular, acicular, granular
occurence                               igneous (mafic), metamorphic (high grade)
TwoV                                    1 2
relief                                  3 
pleochroism.2                           green, brown, blue
birefringence                           5 8 9 10 11 12
cleavage.2                              {110} typical pyroxene cleavage at 87¡