Uthman bin 'Umar bin Fars عثمان بن عمر بن فارس · The Book of Adornment

"Umar said to Suhaib: 'Why do I see you wearing a ring of gold?' He said: 'One who was better than you saw it and did not criticize it.' He said: 'Who was that?' He said: 'The Messenger of Allah .'"

"I bear witness that 'Imran narrated to us, he said: 'The Messenger of Allah forbade wearing silk, and gold rings, and drinking from Al-Hanatim.'"

"The Messenger of Allah forbade me from wearing gold rings, and from garments of Al-Qassi, and garments dyed with safflower, and reciting Qur'an while bowing."

"The ring of the Prophet was of silver, and its stone (Fass) was made of silver too."