Signet rings are also known as seal rings and usually bear a seal and/or are engraved with personalized designs. They are worn by nobles on the small or fifth finger of non-leading hand. They are often a part of royal family's jewels and are a sign of rank and authority.
1 Additional Answer
The signet ring is usually worn on the little finger of the left hand but it can also be worn on the ring finger or as one would wish to wear it. This is because there are no rules as to which finger the ring should be worn on.
A seal is a device for making an impression in wax, clay, paper, or some other medium, including an embossment on paper, and is also the impression thus made. The original purpose was to authenticate a...