Musannaf Ibn Abi Shayba 35:400

'Abdullah ibn al-Mubarak narrated to us, from Sa'id ibn Yazid, who said: I heard Khalid ibn Abi 'Imran narrating from Hanash, from Fudalah ibn 'Ubayd, who said: A necklace containing beads suspended 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 seven dinars or nine. 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." He said: So he returned it until he separated them.