Well, one thing is certain. It's not a paperweight!
Or is it ...? This is a subject that I can easily get drawn into, especially with all the glass animals and other things that are sold and described as "paperweights". But some may well have been made as paperweights. On the other hand, anything that could hold down paper could be
used as a paperweight ... like a house brick, or a computer (for large sheets of paper) and so on, but does that mean they are paperweights?
Seriously thogh, I tend to agree that this item is more likely to be a lid for something. The other way up would be too unstable for a stand-alone item. Sue's idea of a larger vase would seem to be reasonable, particularly if it were a broad shouldered shape - sort of "urn-like" and had a clear glass foot. That would look quite neat.