I've got way too much on my plate already...

[Jinx999]

You can get decent glass from pure silica (only using sand, no added fluxes like the variouls carbonates). However, pure silica has a very high melting point and has a much narrower workability range than a normal glass composition. You are unlikely to get good results simply because it is more difficult to do. There is no fundamental reason why you can't make pure silica glass.