An engagement ring, also known as a betrothal ring, is a ring indicating that the person wearing it is engaged to be married, especially in Western cultures. A ring is presented as an engagement gift by a partner to their prospective spouse when they propose marriage to represent a formal agreement to future marriage. In most Western countries, engagement rings are usually worn only by women, and they are typically adorned with diamonds. In some countries, partners wear matching rings, and engagement rings may also be used as wedding rings. In the Anglosphere, the ring is customarily worn on the left hand ring finger, but customs vary across the world.
Engagement rings have been common in Western countries since at least the time of the Roman Empire. They began to feature diamonds during the Renaissance, and became especially closely associated with diamonds after a marketing campaign by the De Beers Group between 1939 and 1979.
