Is it permissible for the one who finds treasures buried in another's land to own them, or do they belong to the landowner?

If a treasure is found:

Either it has an Islamic mark on it. In this case, it is treated as a lost item (Luqatah) that must be announced for a year. After that period, it belongs to the finder, unless the landowner claims it, in which case it is theirs.

Or it has a pre-Islamic mark on it. In this case, one-fifth of it must be given out and spent on the channels of zakat (definition). Scholars have agreed that it belongs to the finder, unless the landowner claims it, in which case their word is to be accepted.

Or it has no mark on it. In this case, the matter should be presented to the Sharia (definition) judiciary.