Template:Alexandrite

From The Gemology Project
Jump to: navigation, search
Alexandrite
Chemical composition Al2(BeO4)Beryllium aluminum oxide
Crystal system Orthorhombic
Habit Tabular, pseudo-hexagonal
Cleavage Imperfect prismatic
Fracture Weak, conchoidal
Hardness 8.5
Optic nature Biaxial +
Refractive index 1.744 - 1.755
Birefringence 0.009
Dispersion Low, 0.014
Specific gravity 3.70 - 3.72
Lustre Bright vitreous
Pleochroism Strong