I think I was wrong about the Prophet's ring bearing an impression of an Elephant - but he did wear a silver ring with his name inscribed on it:
Men Wearing A Silver Ring — Is It A Sunnah? [Sept. ‘06]
Commentary by Adil Salahi — Arab News
Some people insist that it is a Sunnah to wear a ring, citing the Prophet's (peace be upon him) example and saying that the Prophet's companions did the same. We have a large number of Hadiths mentioning the Prophet's action on this point. We need to look at these in order to establish whether wearing a ring is a Sunnah, or only recommended, or merely a permissible thing that carries no special importance.
The first Hadith we look at is reported by Ibn Omar: "The Prophet, peace be upon him, acquired a gold ring and he used to wear it in his right hand. People did the same, acquiring gold rings. The Prophet, peace be upon him, discarded his ring and said: 'I will never wear it.' People also discarded their rings." (Related by Al-Bukhari and Muslim.)This Hadith mentions an event that took place before the prohibition of wearing gold and silk by men. The Hadith makes clear that wearing gold is unacceptable in Islam. The Prophet, peace be upon him, wore his ring for a short period, then he learned that it was unacceptable and he discarded it, saying he would never wear it again. This is an indication of disapproval that does not indicate prohibition. The prohibition is made clear in a Hadith which mentions that the Prophet, peace be upon him, held a piece of gold in his right hand and a piece of silk in his left hand and said: "These two are forbidden to men of my community, permissible for women." This is certainly a definitive statement, with clear prohibition of gold and silk for men.
Rings can be made of other material. Indeed the Prophet, peace be upon him, used a ring of silver. Anas reports: "When the Prophet, peace be upon him, wanted to send a letter to the Byzantines, he was told, 'They will not read your letter unless it carries a seal.' He acquired a ring made of silver and carved on it 'Muhammad Rasul Allah,' which means 'Muhammad, God's Messenger'. I can now see its whiteness in his hand." (Related by Al-Bukhari, Muslim, Abu Dawood and Al-Tirmithi.)These two Hadiths are confirmed by two more reported by Abdullah ibn Umar: "The Prophet acquired a ring made of silver which he used as a seal, but did not wear." (Related by Al-Tirmithi.) "The Prophet acquired a gold ring, but then discarded it, then he acquired a silver ring and carved on it 'Muhammad Rasul Allah.' He said: 'No one should carve the same as I have carved on this ring of mine.' When he wore it, he would turn its stone inside to make it next to his palm. This was the ring that fell in the Arrees well when Muayqeeb had it." (Related by Muslim and Al-Tirmithi.)
These four Hadiths give us a clear picture. The Prophet, peace be upon him, first had a gold ring, but he did not wear it long before discarding it. This was not an uncommon thing by the Prophet, peace be upon him. He might do something then stop it to indicate disapproval. Thus the disapproval will come on the basis of an experience which might tell the Prophet, peace be upon him, that it is better left out. In the case of gold rings the disapproval was carried further, to indicate clear prohibition for men, specifically stated in another Hadith. We then learn that the Prophet, peace be upon him, acquired a silver ring, and this time it wa s needed for a specific purpose. He wanted to send a message to the Byzantine emperor calling on him to adopt Islam. He was told, however, that without a seal his message would not be entertained. Therefore he had his ring carved so as to serve as a seal. Hence he is reported to wear it only sparingly. Many other Hadiths speak of the Prophet's rings, but they confirm what we have already stated.
It is useful, however, to quote as many as possible of these Hadiths. Anas reports: "The Prophet's ring was made of silver, and its stone was part of it." (Related by Al-Bukhari.) In two other authentic reports by Anas, the Prophet's silver ring had an Abyssinian stone, which he turned to the inside of his hand. Anas also reports that "The carving on the Prophet's ring was in three lines: Muhammad in a line, Rasul in another, and Allah in a line." (Related by Al-Bukhari, Muslim, Abu Dawood, and Al-Nassa’ie.) This is further clarified by a report mentioning that the name of God, Allah, was in the top line, and the Prophet's name, Muhammad, was in the bottom line. This is because the Prophet, peace be upon him, did not wish his name to be above God's name. Further Hadiths reported by Abdullah ibn Ja’afar and Jabir confirm that the Prophet, peace be upon him, used to wear his ring in his right hand. Anas also confirms this and adds that the stone was turned inside, so as to be next to his palm. However, this was not always the case, as indicated by the following Hadith reported by Anas: "The Prophet, peace be upon him, used to wear his ring in this finger, pointing to his little finger of his left hand." (Related by Muslim.) This is confirmed by the following report by Abdullah ibn Umar: "The Prophet used to wear his ring in his right hand, but later he changed, wearing it in his left hand." Another report by Ibn Umar states: "The Prophet used to wear his ring in his left hand, turning its stone inside." (Related by Abu Al-Shaykh.)
These Hadiths mean that the Prophet, peace be upon him, did not wish to maintain a single pattern. This was part of his style, changing patterns in order to indicate their permissibility and that there is no particular preference. The only thing that we note to have been consistently done by the Prophet, peace be upon him, with regard to wearing a ring is that he turned the stone inside. This is because the stone is the most attractive part of the ring, and it is often the part that invites admiration. The Prophet, peace be upon him, always preferred what was ordinary, and not particularly eye-catching or showy. However, he did not indicate that people should wear their rings with the stone turned inside. Moreover, he wore his ring at times in his right hand, and in his left one at other times. This tells us that both are perfectly permissible. The tradition in many countries nowadays is that while engaged to be married, a prospective couple wear their rings in their right hands, and they change to their left hands after their wedding. There is nothing in the Prophet's action to indicate disapproval. Therefore, it is permissible.
from:
http://www.ourdialogue.com/answers/arti ... ticle=3283