What is the ruling on wearing a ring on the thumb, and what is the ruling on wearing a ring with a large stone? Is this considered a display of fame? And what is the criterion in this matter?

It is permissible for a man to wear a silver ring, but it is disliked to place it on the thumb. The Sunnah is to wear it on the little finger of the left hand. Some scholars have specified the weight of a silver ring as a mithqal or less, while others have not specified a particular weight. As for rings made of materials other than silver, there is no specific weight for them, and they remain permissible as long as they do not reach the point of extravagance. The Malikis permitted wearing rings of agate, tin, wood, and leather. The Hanbalis permitted wearing rings of jewels, emeralds, rubies, turquoise, pearls, and agate. The Hanafis permitted wearing rings of all stones. The Shafi'is permitted wearing rings of materials other than silver, such as copper or other metals. It is permissible for the ring to have a stone or not. The stone is considered part of the ring's weight for those who consider weight. If weight is not considered, then custom is the reference for the size of the stone, as long as it does not reach the point of extravagance or blameworthy ostentation.