Musnad Ahmad 5:254

'Affan narrated to us, Shu'bah narrated to us, Abu Ishaq informed us, I heard Hubayrah say: I heard 'Ali say: "The Messenger of Allah (ﷺ) forbade me — or the Messenger of Allah (ﷺ) forbade — the gold ring, the *qassi* (garment containing silk), and the *maytharah* (a saddlecloth or cushion made of silk or animal fur)."