Hadith 505890
Chapter 17: Zakat - كتاب الزكاة
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، وَعَنْ أَبِي سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " فِي الرِّكَازِ الْخُمُسُ " .
Yahya related to me from Malik from Ibn Shihab from Said ibn al- Musayyab and from Abu Salama ibn Abd ar-Rahman from Abu Hurayra that the Messenger of Allah, may Allah bless him and grant him peace ,said, "There is a tax of a fifth on buried treasure."
Reference Muwatta Malik 505890
USC-MSA web (English) reference : Book 17, Hadith 9