Bought this "interesting" piece today, diameter 23 cm, height 16 cm, base is ground but not polished.
There are 6 indentations which build internal strips connecting top and bottom (sorry, I am not able to describe this technically in English, not even in German I guess).
Ideas on maker, date,...? (It was pretty dirty, so it may have been around a while; had to clean off even mice droppings

And I am wondering what it is meant for: is it merely an object, or a bowl, a lampshade,...? (a small bulb would fit in the opening, but as the base is not a circle I am wondering what the fixture would have looked like, then).
The technique reminds of some Pavel Hlava pieces (not the quality, I am afraid).
Any input greatly appreciated!
Michael