Sahih al-Bukhari 6912
Narrated Abu Huraira:
Allah's Messenger (ﷺ) said, "There is no Diya for persons killed by animals or for the one who has been 
killed accidentally by falling into a well or for the one killed in a mine. And one-fifth of Rikaz 
(treasures buried before the Islamic era) is to be given to the state."
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، حَدَّثَنَا اللَّيْثُ، حَدَّثَنَا ابْنُ شِهَابٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، وَأَبِي، سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏
"‏ الْعَجْمَاءُ جُرْحُهَا جُبَارٌ، وَالْبِئْرُ جُبَارٌ، وَالْمَعْدِنُ جُبَارٌ، وَفِي الرِّكَازِ الْخُمُسُ ‏"‏‏.‏