Well, this certainly looks like a K’tonian artifact but if you notice the grooves on the bottom, that means that this was actually made on a Jiyong potters wheel as an imitation of the K’tonian style of pottery. This is a replica, albeit a 700 year old, very good replica. I do happen to know a buyer who would be willing to pay you for it.
If you want to add a "supernatural" touch to your campaign, define the rules of magic and the universe. Make your players comfortable with those rules. Then your new supernatural creatures must then break those rules.