Idocrase / Vesuvianite

Color: Green to olive/green, yellow/green

Moh’s Hardness: 6.5

Refractive Index: 1.71

Critical Angle: 35.79°

Specific Gravity: 3.32-3.42

Cleavage: Imperfect

Fracture: Uneven, splintery

Dispersion: Moderately high (.019)

Heat Sensitivity: Low

Dichroic: weak

Birefringence (double refraction): Weak (.005)

Crystal Structure: Tetragonal Cutting

Treatments: Generally none