Musannaf Ibn Abi Shayba 13:226

Ibn al-Mubarak narrated to us, from Sa'id ibn Yazid, who said: I heard Khalid ibn Abi 'Imran narrating from Hanash, from Fadala ibn 'Ubayd, who said: A necklace containing beads attached with gold was brought to the Prophet, may Allah bless him and grant him peace, on the day of Khaybar. A man had purchased it for nine dinars or seven. He came to the Prophet, may Allah bless him and grant him peace, and mentioned that to him. He said: "No, until you separate between them." He said: "I only intended the stones." He said: "No, until you separate between them."