Crazy how this was one of Jim Gillette's big selling points and now youtube is full of videos of randoms doing it unamplified. You can do it on pretty much any glass as long as the glass rings nicely and has a strong fundamental pitch that isn't swamped with odd-order harmonics. If you're struggling, use a diamond ring if you're wearing one, or a glass cutter or someting, and make a tiny scratch anywhere on the glass. Once the surface is scratched, it's10X easier.
Says the one with no content and no life. He has won awards for what he's done. Maybe before you talk you should look in the mirror stop self projecting he's one of the funniest comedians to ever exist. You are just numbskull idiot probably a child that doesn't even know what talent is.