Thank you Robert!
I like that whole Zemek range shown in CGR 1958/6; as far as I can see there is no glassworks specified...
I would have thought Mstisov, too.
Wayne has pics of a Uranium green one in his encyclopedia >> Link
And of a fabulous vase, too.
The seller I bought it from had several very tempting pieces (Kotik propeller vase, Jelinek "Olympie" ashtray), but I decided to go for this one