Musnad Ahmad 1153:38

Muhammad ibn Salamah narrated to us, from Khasif and Marwan ibn Shuja', he said: Khasif narrated to me, from Mujahid, from Aisha. And Marwan said: I heard Aisha saying: She said: When the Messenger of Allah, peace and blessings of Allah be upon him, forbade the wearing of gold, we said: "O Messenger of Allah, may we not tie musk with something of gold?" He said: "Can you not tie it with silver, then smear it with saffron, so it becomes like gold?"