Sunan an-Nasa'i 5288
سنن النسائي#5288SahihIt was narrated that Ibn 'Umar said:"The Prophet [SAW] wore a ring of gold, then he discarded it and wore a ring of silver on which were engraved (the words) 'Muhammad Rasul Allah.' Then he said: 'No one should copy this inscription of mine.' And he wore the stone (Fass) toward his palm
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 ZaiHasan
In-book reference: 48:249