I'm kinda curious if the under-glaze (or portions of) looks hand painted (as in highlighted/shaded areas) on your cool little item .
I suppose you could check it out with a loupe to see if the decorations are decals or not .... my eyes are fooled by the images , though , as it appears to be a cast (3-D) round 'tile' to them .
Looks like it could have many decorative uses !