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Chemical composition BeAl2O4
Crystal system Orthorombic
Habit Pseudo-hexagonal twins
Cleavage Weak to moderate
Fracture Conchoidal to uneven
Hardness 8.5
Optic nature Biaxial +
Refractive index 1.74-1.75
Birefringence 0.009
Dispersion Low, 0.014
Specific gravity 3.72
Lustre Bright vitreous
Pleochroism Moderate to strong