Sunan An-Nasa'i

It was narrated from Ibn 'Umar that:The Messenger of Allah [SAW] put on a ring of gold, and he used to wear its stone (Fass) next to his palm. Then the people started to wear rings of gold too. Then the Messenger of Allah [SAW] threw it away, and the people threw their rings away too. Then he took a ring of silver and he used to seal letters with it, but he did not wear it