Optically, crystalline quartz is used extensively as a wave retardationmedium, using the birefringent properties for use in quarter-wave platesand in polarizers. Quartz is mined naturally, but more commonly producedsynthetically in large long faceted crystals. Quartz is positive birefringent.

Item	Quartz Crystal	Transmission of Quartz Crystal
Wavelength	150-4000nm
Size	0.1-100mm
Orientation	<6 arc min
Parallelism	<1 arc sec
Surface Quality	10/5
Flatness	λ/10
Clear Aperture	>95%
Coating	Upon Customer's Specification