group epidote
system monoclinic
formula see properties
optic biaxial pos / neg
Too-Vee 40 - 90 (neg) / 90-57 (pos)
relief.1 high pos
min. index 1.690 / 1.823
color brown, green
pleochroism yes
birefringence.1 0.013 - 0.036
cleavage yes
elongation yes
extinction parallel, inclined
angle 26 - 72¡
alteration ***
habit.1 columnar, bladed ,acicular, anhedral
occurence igneous (accessory, granitic), metamorphic (skarn), hydrothermal
TwoV 1 2
relief 3
pleochroism.2 yellow, brown
birefringence 5 7 8 9 10 11 12 13
cleavage.2 {001} fair, {110} and {100} poor