The Messenger of Allah ﷺ said, "On buried treasure, a fifth is due."
حدثنا نصر بن علي الجهضمي حدثنا أبو أحمد عن إسرائيل عن سماك عن عكرمة
قال رسول الله ﷺ في الركاز الخمس
No references are available.
[Sahih] Ahmad reported it, 1/314, via the route of Israil, from him, and he also reported it from Abu Ahmad, as noted in Atraf Musnad, 30/207. Busiri graded it sahih, but its chain is daif, see hadith 171 for its defect. The preceding hadith serves as a corroborating witness for it, and with that, the hadith is sahih.