Here is a vintage glass shade or diffuser bowl for a ceiling light fixture, I'm guessing from the 1920s to 1940s. It measures about 10 inches across and 5 inches deep, and has three holes for hanging from chains. The shade is blue, with a center medallion, two borders, and a raised design of grapes and leaves left clear. 

This shade has a little bit of roughness at the rim and minor cracking and chipping at the chain holes (see photos). There are some scratches and mold lines.