hello and welcome to the GMB

regret to say that this forum doesn't discuss values - apart from the fact that such things are known to come and go with fashion, there is the obvious aspect that different people have different ideas as to what something is worth.
Must say I'm a big fan of the Ipomoea group - those blues are mind blowing (so apparently is the plant when ingested

) - but unfortunately I can't help with your glass.
There is a type of clear and coloured decoration called 'coralene' which shows as very small pieces of glass fused to the main body to create shapes and patterns, but am sure this isn't 'coralene', and enamelling on glass goes back a long way and was used probably in most countries, so this on its own will not help.
Other than that I've no idea, but fingers crossed someone might be able to help. From where did you source the piece - an estate sale perhaps?