Again, we don't discuss valuations here Joe.
Anything is only worth what somebody else is willing to pay for it. That depends on who has it, how it is advertised, who the audience is, how much they know, how much spare cash they have, how much they want it etc. etc. etc.
The best way to get an idea is to find something the same at auction and watch to see what it sells for. Then consider the under bidder's price - because you've already lost the high bidder from your audience.
We're just interested in the glass itself here.
Don't worry about having done it - you're new!
I think this is just a very contemporary decorative thing. You might well see similar in TKMaxx.