Topic: Optical materials and their properties

[Astronuc]

Among the more esoteric areas of materials science -

http://www.almazoptics.com/material.htm

I found this while looking for properites of lithium fluoride (LiF) -
http://www.almazoptics.com/LiF.htm

Another interesting material is sapphire, a form of aluminum oxide (Al₂O₃), also called 'alumina'.

http://www.almazoptics.com/sapphire.htm

Astrosital (Russian equivalent to Zerodur) - used as a substrate for astronomic mirrors.
http://www.almazoptics.com/Astrosital.htm