The Prophet ﷺ used to wear his ring on his left hand, with the stone facing the inside of his palm.
حدثنا نصر بن علي حدثني أبي حدثنا عبد العزيز بن أبي رواد عن نافع
أن النبي ﷺ كان يتختم في يساره وكان فصه في باطن كفه
Grading, its chain is daif. Bayhaqi reported it in Shuab al-Iman, hadith 6375, from the hadith of Abu Dawud with the same chain, and the hadith is irregular.The hadith of Usama bin Zayd is found in Muslim, hadith 2091, in abridged form. Muslim also reported, hadith 2095, from Anas, who said, "The ring of the Prophet was on this," pointing to the little finger of his left hand.