Commitment rings are used to express love and symbolize unity between two people. Some people refer to commitment rings as promise rings.
Commitment rings are worn on the third finger of a person's left hand. They are worn on this finger because ancient cultures believed that the specific finger contained the veins the lead to the heart. Couples often give each other commitment rings when they are not ready to take the step toward engagement. They often choose rings that have symbols or gemstones that have a personal significance. Some even choose to add the other person's birthstone to their ring.