Abu Huraira reported God’s messenger as saying, “No retaliation is payable for a wound caused by a dumb animal, or for an accident in a well or a mine, but a fifth is payable on buried treasure.” * (Bukhari and Muslim.) * The word used (rikaz) is applied to treasure buried by people in pre-Islamic times; but the word may also mean metal in mines.
Hadith Referenceمشكوة المصابيح / كتاب الزكاة / 1798
Hadith Gradingالألبانی:مُتَّفَقٌ عَلَيْهِ | زبیر علی زئی:متفق عليه
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «متفق عليه، رواه البخاري (1499) و مسلم (1710/45)»