Musannaf Ibn Abi Shayba 16:952

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Ibn Mughaffal narrated to us, from Nafi’, who said: The sword of Umar was decorated with silver. I said to him: "Did Umar decorate it?" He said: "I have seen Ibn Umar wearing it."