What is the ruling regarding treasure (Rikaz) found in unowned or abandoned land?

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When treasure (Rikaz) is found in unowned land (Mawat) or land whose owner is unknown, such as land containing ancient ruins, mounds, or pre-Islamic walls and graves, it is subject to the Khums (one-fifth levy) without dispute. This ruling applies if the treasure is found on the surface, in an unused path, or in a ruined village. This is evidenced by the report from 'Amr ibn Shu'ayb, on his father's authority, from his grandfather, that the Messenger of Allah, peace be upon him, stated concerning lost items (Luqatah) found in a frequented path or an inhabited village, that it should be announced for one year, and if the owner appears, it is returned, otherwise it belongs to the finder; but what is not found in a frequented path nor in an inhabited village, then the Khums is due on it, just as for Rikaz.