Template:Hiddenite

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Hiddenite
Chemical composition LiAl(SiO3)2

Lithium aluminum silicate

Crystal system Monoclinic
Habit Prismatic
Cleavage Perfect, prismatic
Fracture Uneven
Hardness 7
Optic nature Biaxial +
Refractive index 1.66-1.68
Birefringence 0.015
Dispersion Low, 0.017
Specific gravity 3.18
Lustre Vitreous
Pleochroism Strong