I went back to FIL's house today got some really cool pictures of some real interesting stuff.
This has only been described to me as a 'poison pot'. Where hunters (?) would keep their poison, and dip their arrowheads in it...
There are no identifying marks, it is very heavy. at first glance it looks like stone, but the bottom was buffed to a shine. not sure what kind of metal it would be. There are etchings in the bottom that I can only guess my FIL made.
I'm not even sure where to start looking for this one...