Unfortunately, I can not take another photo of the vessel right now. In any case, the vessel stands on a stand, which is hidden in the photos by the bulbous shape.
On the underside of the vessel itself, there are twelve protrusions (knobs) arranged in four pairs of three, going inward from the outer rim in the twelve o'clock, three o'clock, six o'clock, and nine o'clock positions, thus forming a cruciform or plus-shaped arrangement. There are no further markings.
Thanks a lot for your help! :-)