Transparent Aluminum

Aluminium Oxynitride

Also called AION and normally sold by the name ALON.

It is glass-like very strong ceramic used as the crucial outer layer of experimental transparent armor being considered by the US Air Force, for the windows of armored vehicles. Other applications include semiconductors and retail fixtures.

Reference

Air Force testing new transparent armor by Laura Lundin, Air Force Link, October 17, 2005, retrieved June 25, 2008