hello Trudy......... regret I'm going to be rather negative, unfortunately.
This grading of blue, violet and orange would seem to suggest Chribska, but the lack of clear casing - many Chribska pieces like this have massively clear bases, plus the fact that I can't find the shape - would suggest not. You don't make any mention of casing.
I somehow don't get the feeling it's Murano.
You might care to continue to looking here...........
http://www.20thcenturyglass.com/glass_encyclopedia/bohemian_glass/chribskaglass_home.htm ... which does include a lot of material from that factory. Since the Czech glass experts remain silent, then must assume this not an easy piece to id.
A very big thanks to Jindrich for manking available his catalogues of Czech glass
