Template:Datolite

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Datolite
Chemical composition CaB[OH|SiO4]
Crystal system Monoclinic
Habit Short prisms, porcelaneous cryptocrystalline aggregates
Cleavage None
Fracture Conchoidal to uneven
Hardness 5 - 5.5
Optic nature Biaxial -
Refractive index 1.622 - 1.670
Birefringence 0.044
Specific gravity 2.95 - 3.0
Lustre Vitreous to porcelainous