It is narrated from Sayyiduna Abdullah bin Ja'far (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) used to wear a silver ring on his right hand.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13806
Sayyiduna Abdullah bin Ja'far (may Allah be pleased with them both) said to his daughter, when he took her to al-Hajjaj: When he comes in to you, say: "La ilaha illallahul-'Aliyyul-'Azim, subhanallahi Rabbil-'Arshil-Karim, al-hamdu lillahi Rabbil-'alamin (There is no god but Allah, the Most High, the Magnificent; glory be to Allah, Lord of the Noble Throne; all praise is for Allah, Lord of the worlds)." And he held that whenever the Messenger of Allah (peace and blessings be upon him) was struck by severe hardship, he used to say these very words. So she said these words, and he could not reach her.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13807