Well, I suspect my candleholder is the sort where you can have either the metal as base up, or the glass up, depending on the size of the candle you want to lit. I've attached a few pictures from all sides.
One similarity I notice with the Jurnikl piece is that the sides of the glass block in my piece aren't exactly straight, but they are slightly round (well visible in the third picture). That is different from your picture, Dirk, where the sides look very straight to me.
I would be interested to find out if Rudolfova ever attached bits of metal to their glass ware. Or maby other Czech or German factories just copied the basic design and made their own version.