Maliks Muwatta Book 17, Hadith Number 1.

Section : Things on which Zakat must be Paid.

Yahya related to me from Malik from Amr ibn Yahya al-Mazini that his father said that he had heard Abu Said al-Khudri say that the Messenger of Allah, may Allah bless him and grant him peace, said, “There is no zakat on less than five camels, there is no zakat on less than five awaq (two hundred dirhams of pure silver) and there is no zakat on less than five awsuq (three hundred sa).”