Allah's Messenger (ﷺ) wanted to write a letter to a group of people or some non-Arabs. It was said to him, "They do not accept any letter unless it is stamped." So the Prophet (ﷺ) had a silver ring made for himself, and on it was engraved: 'Muhammad, the Messenger of Allah'. .. as if I am now looking at the glitter of the ring on the finger (or in the palm) of the Prophet (ﷺ) .
Sahih al-Bukhari Book 77, Hadith 89
← Previous Hadith A woman came to the Prophet (ﷺ) and said, "I have come to present myself to you (for marriage)." She kept standing for a long period during which period the Prophet (ﷺ) looked at her carefully. When she stayed for a Long period, a man said to the Prophet (ﷺ) "If you are not in need of her, then marry her to me." The Prophet (ﷺ) said, "Have you got anything to give her (as Mahr)?" The man said, "No." The Prophet said, "Go (to your house) and search for something." The man went and came back to say, "By Allah, I could not find anything." The Prophet (ﷺ) said, "Go again and search for something, even if it be an iron ring." He went again and came back saying, "No, by Allah, I could not get even an iron ring." The man had only an Izar and had no Rida' (upper garment). He said, "I will give her my Izar as Mahr." On that the Prophet (ﷺ) said, "Your Izar? If she wears it, nothing of it will remain on you, and if you wear it nothing of it will be on her" The man went aside and sat down When the Prophet (ﷺ) saw him leaving (after a while), he called back and asked. "How much Qur'an do you know (by heart)? He said, 'I know such and such Suras," naming some Suras. The Prophet (ﷺ) said, "I marry her to you for the amount of Qur'an you know (by heart).

Sahih al-Bukhari Book 77, Hadith 88 Next Hadith → Allah's Messenger (ﷺ) had a silver ring made for himself and it was worn by him on his hand. Afterwards it was worn by Abu Bakr, and then by `Umar, and then by `Uthman till it fell in the Aris well. (On that ring) was engraved: 'Muhammad, the Messenger of Allah."

Sahih al-Bukhari Book 77, Hadith 90