Epidote-Clinozoisite Ca2(Al,Fe)3(OH)(SiO4)3

Optical Properties:

Biaxial + or -; 2V 56 to 89 degrees; colorless (clinozoisite) to yellowish green (epidote) pleochroism (upper right photo); birefringence weak in clinozoisite, to strong in epidote; clinozoisite typically has anomalous blue interference color (upper left photo); extinction is parallel in elongate grains.

Occurrence:

Commonly occurs in low to medium grade metamorphic rocks, and as hydrothermal or deuteric alteration in igneous rocks.

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