to avoid any misunderstanding, this bit of glass is going to end up on Ebay - I will of course refer back to this site re any help you are able to give.
This is a big old piece of glass - 25 cm diameter
It's fairly rough looking (not that I could make it !) - I'm guessing a student somewhere, but any thoughts gratefully received.
On the foot are three small ground marks - it doesn't look accidental.
Gareth