Wollastonite

xpl 10*

ppl porphyroblast with wollastonite near dodecahedral shape vesuvianite (higher 10*

group                                   inosilicate
system                                  triclinic
formula                                 CaSiO3
optic                                   biaxial neg
Too-Vee                                 36 - 60¡
relief.1                                mod to high pos
min. index                              1.616 / 1.656
color                                   colorless
pleochroism                             no
birefringence.1                         0.013 - 0.017
cleavage                                yes
elongation                              yes 
extinction                              inclined, nearly parallel
angle                                   5 - 10¡
alteration                              pectolite, calcite, apophyllite
habit.1                                 fibrous, columnar, acicular
occurence                               metamorphic (high grade, carbonate)
TwoV                                    1 2
relief                                  2 3
pleochroism.2                           
birefringence                           5 6 7 
cleavage.2                              {100} perfect, {001} good, {102} good