high optical transmittance CaF2 crystal has the following exceptional properties that makes it a ... )178 [100], 160 [110]kg/mm2Dielectric Constant6.76 ,105HZCrystal Typecubic, CaF2 type structureCleavage Planes(111) Refractive IndexWavelength, µm0.190.210.250 ... /5 to MIL-O-13830AParallelism6 arc secondsFlatnessλ/20 @ 632.8nm CaF2