Sahih Bukhari Volume 007, Book 072, Hadith Number 765.
Narrated By Abdullah : The Prophet had a golden ring made for himself, and when he wore it. he used to turn its stone toward the palm of his! hand. So the people too had gold made for themselves. The Prophet then ascended the pulpit, and after glorifying and praising Allah, he said, "I had it made for me, but now I will never wear it again." He threw it away, and then the people threw away their rings too. (Juwairiya, a sub-narrator, said: I think Anas said that the Prophet was wearing the ring in his right hand.)