Sunan an-Nasa'i 5196
سنن النسائي#5196SahihIt was narrated from Anas that :The Prophet [SAW] wore a ring of silver with an Ethiopian stone (Fass), on which was inscribed (the phrase): "Muhammad Rasul Allah (Muhammad the Messenger of Allah)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih - Agreed Upon
In-book reference: 48:157