TOURMALINE
Species: Tourmaline
Mohs Hardness: 7 to 7.5 out of 10 Color: Nearly all colors RI: 1.624 to 1.644 (+/-0.005) Birefringence: Usually 0.018 to 0.020 SR/DR/AGG: DR Clarity Type: Type I - Green, Type III - Pink & Watermelon, Type II - All Other Colors Optic Character: Uniaxial negative Pleochroism: Medium to strong, usually two tones of the gem's body color. Spectrum: Varies Fluorescence: Varies SG: 3.06 (+0.20 / -0.06) Routine Treatments: None Additional Enhancements: Irradiation, heating, coating |