Hadithcore
Mishkat al-Masabih, 4387

He said the Prophet’s signet-ring was of silver as was also its stone. Bukhari transmitted it.

وَعَنْهُ أَنَّ نَبِيَّ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ خَاتَمُهُ مِنْ فِضَّةٍ وَكَانَ فَصُّهُ مِنْهُ. رَوَاهُ البُخَارِيّ

References1 variant
In-Book Reference
Book 22, Hadith 78