Is an old metal piece found in land that does not belong to the finder and is owned by another person a natural right of the finder, or should the landowner take from it, and what is the share of each?

Scholars have differed regarding the rikāz (buried treasure) found in the land of a Muslim or a protected dhimmī: whether it belongs to the finder or to the landowner. The majority opinion is that it belongs to the landowner. Therefore, the finder of this Roman piece has no right to it. He ought not to have disposed of it and should have handed it over to his brother, the landowner. He must now inform him of what happened. If the landowner absolves him, then alḥamdulillāh (all praise is due to Allah). Otherwise, he owes him its value on the day he took possession of it.