Basic Properties
Transparency  Range	High transmittance from 0.4 to 5mm
Crystal Symmetry	Zircon Tetragonal, space group D4h
Crystal Cell	A = b = 7.12 Å C = 6.29 Å
Density	4.22 g/cm³
Mohs Hardness	5, glass-like
Hygrocopic Susceptibility	Non-hygroscopic
Thermal Expansion Coefficient	?a =  4.43 x 10-6 / K ?c =  11.37 x 10-6 / K
Thermal Conductivity Coefficient	// C: 5.23 W/m/K ^ C: 5.10 W/m/K
Crystal Class	Positive uniaxial  with n0 = na = nb , ne = nc
Thermal Optical Coefficient	dna/dT = 8.5 x 10-6 /K dnc/dT = 3.0 x 10-6 /K
List of optical crystals