group epidote
system orthorhombic
formula Ca2Al3O(Si2O7)(SiO4)(OH)
optic biaxial pos
Too-Vee 0 - 60¡
relief.1 high pos
min. index 1.685 / 1.725
color colorless
pleochroism yes
birefringence.1 0.005 - 0.020
cleavage yes
elongation yes
extinction parallel
angle 0¡
alteration not commonly altered
habit.1 columnar, prismatic, bladed, acicular, anhedral, granular
occurence igneous (accessory, ultramafic), metamorphic (medium grade, carbonate)
TwoV 1 2
relief 3
pleochroism.2 pink, yellow
birefringence 1 2 3 4 5 6 7 8
cleavage.2 {100} perfect, {001} poor