[perezfan]

You can do it yourself with a sharp blade or scissors too. It takes a lot patience though, and you have to be willing to destroy a few before you get it right. So maybe taking it to a professional would cost about the same in the long-run.

All of the ones you see in this photo were done by me, by hand...

That said, it's lots easier to just slip them in a mylar window and frame them (as suggested above). The depth of the slab adds lots of unnecessary complexity to the process....