you can pick it up at hardware stores, I have old fashioned double hung windows in my house, and for awhile, my son enjoying running into them to watch them break - so I reglazed my own windows (they are now plexi at the bottom) but yeah, we've had people bring in 'their own glass' for framing, and have to explain to them it's too thick for standard frame moulding - and it usually has a greenish blue tint.