Template:Willemite

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Willemite
Chemical composition Zn2SiO4
Crystal system Trigonal
Habit prismatic; massive
Cleavage indistinct
Fracture Conchoidal to irregular
Hardness 5.5
Optic nature Uniaxial +
Refractive index 1.691 - 1.725
Birefringence 0.028
Dispersion n d
Specific gravity 3.89 - 4.19
Lustre Vitreous to resinous
Fluorescence green to yellow