There is a very, very similar cup but with a dragon on the side by Salviati (1880) in the Zoppi collection (ref. "I colori di Murano '800" pag 142).
The color combination and the tones of avventurine are the same, also same thickness and "touch" (may be same master glassmaker too?), so I agree with Anita about producer and date (Imho better end of 19th century).
Similar pieces are in the Murano glass museum too, in the 4th room.
My only doubt/question is about the "avoglio" (the connection point between stem and cup).
The thickness is correct, but It looks as painted with a kind of gold enamel. Not an usual gold leaf, but a solid enamel, never used in this way in these kind of classic glassworks. Or it is a metallic ring???
May be I don't recognize properly this strange detail from the photo, but at my eyes it looks as something wrong.
I'm just supposing a realistic answer: it may be that the goblet was damaged and restored? May be also a long time agoo?
That solid metal/gold color seems as not part of the original work.... :huh: