It is narrated from Sayyiduna Imran bin Husayn (may Allah be pleased with him) that he saw a brass ring on a man's hand and said: "What is this?" He said: It is for al-wahinah. He said: "Beware! It will only increase you in weakness, and if you die in this state, believing that it benefits you, you will die on other than the fitrah (natural disposition)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15505