Fluorite

 

Color: Colorless, yellow, green, blue, pink, purple, red and orange

Moh’s Hardness: 4

Refractive Index: 1.434

Critical Angle: 44.37°

Specific Gravity: 3.18

Cleavage: Perfect in 4 directions

Fracture: Even to conchoidal, brittle

Dispersion: Very low (.007)

Heat Sensitivity: High, in my experience

Birefringence (double refraction): None

Crystal Structure: Isometric

 

Treatments: Generally none, sometimes can be irradiated.