Abdullah bin al-Harith bin 'Abdul Malik عبد الله بن الحارث بن عبد الملك · The Book of Adornment

The Messenger of Allah had a ring made of gold and he used to wear it with the stone (Fass) against his palm, and the people did likewise. Then he sat on the Minbar and said: "I used to wear this ring and put its stone (Fass) on the inside." Then he threw it away and said: "By Allah, I will never wear it again." And the people threw their rings away.