Sunan an-Nasa'i, Volume 6, Book 48, Hadith 5284 (DarusSalam) ⓘ

It was narrated from Anas that: The Prophet [SAW] had a ring and he said: "We have had a ring made with an inscription, and no one else should copy this inscription." It is as if I can see its shining on the little finer of the Messenger of Allah [SAW].

أَخْبَرَنَا عِمْرَانُ بْنُ مُوسَى، قَالَ حَدَّثَنَا عَبْدُ الْوَارِثِ، عَنْ عَبْدِ الْعَزِيزِ، عَنْ أَنَسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم اصْطَنَعَ خَاتَمًا فَقَالَ ‏ "‏ إِنَّا قَدِ اتَّخَذْنَا خَاتَمًا وَنَقَشْنَا عَلَيْهِ نَقْشًا فَلاَ يَنْقُشْ عَلَيْهِ أَحَدٌ ‏" ‏ ‏.‏ وَإِنِّي لأَرَى بَرِيقَهُ فِي خِنْصَرِ رَسُولِ اللَّهِ صلى الله عليه وسلم ‏.‏