Terry had one very similar: same colours and same painterly application of the colours; also very tall but a bullet shape. Unfortunately I can't find a pic of it and I can't rem what the base was like. I do remember that he was impressed by the weight and general quality and felt that it was a studio piece.
The base of yours also suggests a studio but could be from just about anywhere in the world. Romanian ? Someone perhaps following in the footsteps of Ioan Nemtoi ? Sadly I'm pretty sure that's not his signature.http://artglassbygary.com/glassmaster___ioan_nemtoi.html
When and where did your gran get it ?