Look, I know this is pedantry
But sapphire is not a glass. It is a crystal, crystalline aluminium oxide. And sapphire is a coloured version of it, as is ruby. It's just that its technical name, corundum, doesn't sound sexy. I guess "silicon on sapphire" sounded better than "silicon on corundum" back in the day.
Glass is an amorphous material. That's why you can stress harden it by ion bombardment, which increases the internal pressure at the surface so the glass remains in compression even if it is bent a bit (which is how gorilla glass works). Do the same thing with corundum and you will break the molecular bonds, weakening it.
Biting the hand that feeds IT
