Crystal properties
Crystal Type	trigonal
Transmission Range	0.25 ... 2.3 µm
Refractive Index	no=1,6654 / ne=1,4898 @ 509 nm
Density	2.711 g/cm3 @ 25 °C
Melting Point	894 °C (decomposes)
Molecular Weight	101.9613
Thermal Expansion	13 × 10–6 / K
Hardness (Knoop)	3 Mohs
Young’s Modulus	69.9 GPa
Shear Modulus	35 GPa
Bulk Modulus	98 GPa
Solubility in Water	none
Crystal Structure	Single crystal, synthetic
Application	polarisers
List of optical crystals