Actually, glass is harder than regular steel, it's brittle but harder. If you were to rub steel against glass, glass would win. You can't cut glass with steel tool, you need diamond blade. There are very few metals that are harder than glass, they're either too heavy or too expensive for bike frames. Tungsteen carbide alloy is one of them, if not the only (carbide covered steel), although not by much, not enough to clean-cut glass.

This could provide really tough coating unless it's extremely brittle. It may be to brittle for something like chain where you have crushing forces between the surface of chain and cogs/chainwheels.

It's very cool stuff though

Adam