Rubellite Tourmaline

Color: Red/Purple/Pink

Moh’s Hardness: 7-7.5

Refractive Index: 1.616-1.652

Critical Angle: 38.23°

Specific Gravity: 3.02-3.26

Cleavage: None

Fracture: Uneven, small conchoidal.

Dispersion: Medium (.017)

Heat Sensitivity: Not usually a problem

Dichroic: Strong (many color variations)

Birefringence (double refraction): Medium (.014-.024)

Crystal structure: Hexagonal

Treatments: Heat is sometimes used to lighten rough and get rid of undesirable color... Radiation is used on cut stones to improve color, but it is not commonly used on rough (usually stones are cut first and then irradiate).