Musnad Abu Ya'la al-Mawsili 42:6

Zuhayr narrated to us, Sufyan narrated to us, from ‘Amr ibn Yahya ibn ‘Umarah, from his father, from Abu Sa’id al-Khudri, in a narration, he said: There is no Zakat (charity) on less than five awaq (of silver). There is no Zakat on less than five awsuq (of dates or grains). There is no Zakat on less than five camels (dhuwd).