Window material

Sappire is Al2O3 and Aluminum makes up about 7% of the
lunar material. Getting it in a pure form might be a
trick as you are probably working with Anorthite
CaAl2Si2O8.

Isn't sapphire a compound of aluminum and oxygen?
Both elements in
good supply on the Moon and asteroids.

> taken from
http://www.zetatalk.com/shelter/slideloc/material.htm
>
> One impressive material that could be used for blast
proof windows as
> part of a thin-shell enclosure is Synthetic
Sapphire. It's a clear,
> crystalline material that is stronger and more heat
resistant than
> any other material known to mankind. It can
withstand tensile or
> compressive loads up to 600,000 pounds per square
inch.