Is it obligatory to give one-fifth of the money or buried treasure found in the land of a house that was purchased as charity?

If the buried treasure bears signs of the pre-Islamic era (Jahiliyyah), then one-fifth of it must be given out (as khums), and the remaining part becomes permissible for the finder, based on the Prophet's (peace be upon him) saying: "Regarding Rikaz (buried treasure): one-fifth." However, if the treasure is from what was buried by Muslims, it is treated like lost property (Luqatah) and must be announced publicly for a full year. If its owner is not found, it becomes the property of the finder, with the original owner's right guaranteed if he appears in the future. As for treasure found in land or a house that was purchased or gifted, the preponderant opinion is that it belongs to the finder, because it is not part of the land itself but rather deposited within it. Thus, it becomes the property of its finder, like other permissible things discovered on another's land.