What is the ruling on wearing a ring on the left index finger?

It is permissible to wear a ring on the left or the right hand; both are equally valid as they are established from the Prophet, peace and blessings be upon him. It is disliked for men to wear a ring on the index finger or the middle finger, and this is a disliking of mild prohibition (karahat tanzih). As for the Sunnah, it is for a man's ring to be on the little finger (pinky). A woman may wear rings on any of her fingers.