Another great hunt with all the silvers and the awesome seal ring. The button mold (Crusader stated)is a unique find for sure, being made out of lead how would this work?
It would be a lead-alloy. The buttons they were producing were at least 17th C & also made of Lead, so as soon as low melting point lead hit the cold surface it would turn to solid without heating the mould past its melting point.
You can metal detect in Norway if you have the landowner's permission., Some small areas protected by the state like that grave. Older settlements from before 1537. churches etc