Thanks a lot, Robert!
The Zemek vase you mention is similar indeed, but I thought that he wouldn't use a Skrdlovice blank.
That is why I was leaning towards Stahlikova.
In my copy of the book "Böhmisches Glas Crystalex" (from the late 1970s I guess) is a coloured pic of the Zemek vase, in 2 coloured Sommerso blue and brown (if the colours are true); the text states "Frantisek Zemek, cut vase in coloured glass, 1957, Karlovarske sklo, branch Mstisov".
Michael