How was this piece made?
This piece was made using ancient glassmaking techniques--from how the green glass "canes" were made, to their application to the hot glass surface of to the use of centripetal force to create the "handkerchief" edge. It takes a lot of people with a lot of experience to make one of these delicate pieces.
This technique, called filigree or filigrana, has been used since the 1500’s in the famous Murano glass factory. Check out this video for a demonstration: https://www.youtube.com/watch?v=bLmKQVlSwCw