I get why @quinn_thompson says to try selling it online first, but that can be a real hassle. You have to deal with shipping, people flaking, and fees that eat into your money. For a lot of stuff, I've had way better luck just putting it on a local buy and sell group. You get cash in hand faster and avoid all the headaches.
Well that's a fancy new garage decoration you've got there. Maybe you could just build a whole new house around the glass? Seems easier than admitting you messed up the math. At least it wasn't a custom cut diamond or something, right? Just a very expensive reminder to measure twice.