A friendship ring is a popular type of promise ring. These rings are usually swapped between best friends or sometimes between family members. It may symbolize a sibling type of relationship between non-related friends and a commitment to the friendship. Then there are rings called religious promise rings. These rings feature symbols of faith like a cross, angel, star, or dove. It may also be in a simple band formation, and it can of course be engraved with Scripture or a message.