Information
Specific Gravity: 2.72 ( -0.05 / +0.18 )
Hardness: 7.5 - 8.0
Refractive Index: 1.567 - 1.572 ( +0.017 )
Birefringence: 0.005 - 0.008
Crystal System: Hexagonal
Luster: Vitreous
Chemical Composition: Be₃Al₂Si₆O₁₈
Optical Character: Uniaxial (-)
Pleochroism: Dark Blue And Light Or Greenish-Blue
Transparency: Transparent To Subtranslucent
Color: Blue, Greenish-Blue.
Remark: -