I wasn't really counting on famous Czech designers at this stage, but better to make sure

Thanks for the links, both are interesting in their own way.
Since some of your suggestions hinge on age, I've checked the wear on the base again - if it was produced post, say, 1990, I'd expect less wear than it actually has.
The wear on the bottom of this particular piece of glass is enough to give it a few decades. It's not scratched on the surface, but on the bottom there are two fine rings of lots of tiny, tiny scratches that suggest it has a few decades behind it. My reasoning: the style suggests 60s-70s to me, and if it has enough wear, it is probably a period piece rather than a new retro styled one.
Too bad nobody recognizes it... Oh well, it's a high quality piece, and I'll treasure it regardless.