Template:Tanzanite

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Tanzanite
Chemical composition Calcium aluminum silicate
Crystal system Orthorhombic
Habit Prismatic
Cleavage Perfect, prismatic
Fracture Uneven
Hardness 6.5
Optic nature Biaxial +
Refractive index 1.685-1.707
Birefringence 0.008
Dispersion Low, 0.012
Specific gravity 3.35
Lustre Vitreous
Pleochroism Strong trichroism (dichroism in heated)