In the 20th century, if he could afford it, the typical Western groom privately selected and purchased an engagement ring, which he then presented to his desired bride when he proposed marriage. More recently, couples frequently select an engagement ring together. In countries where both partners wear engagement rings, matching rings may be selected and purchased together. In the United States and Canada, where only women commonly wear engagement rings, women occasionally present their partners with an engagement ring.Like all jewelry, the price for an engagement ring varies considerably dependi on the materials used, the design of the ring, whether it includes a gemstone, the value of any gemstone, and the seller. The price of the gemstones, if any, in the ring depends on the type and quality of the gem. Diamonds have a standardized description that values them according to their carat weight, color, clarity and cut. Other gemstones, such as sapphires, rubies, moissanite, emeralds, have different systems. These may be chosen to honor a family tradition, to use family heirlooms, to be unique, to be socially responsible, to fit the individual's stylistic preferences, or to manage cost. Synthetic stones and diamond substitutes such as cubic zirconias are also popular choices that reduce cost while maintaining the desired appearance.The idea that a man should spend a significant fraction of his annual income for an engagement ring originated from De Beers marketing materials in the early 20th century, in an effort to increase the sale of diamondsIn the 1930s, they claimed that a man should spend the equivalent of one month's income in the engagement ring; later they claimed that he should spend two months' income on it. 2007, the average cost of an engagement ring in USA as reported by the industry was US$2,100.One reason for the increased popularity of expensive engagement rings is its relationship to human sexuality and the woman's marriage prospects. Until the Great Depression, a man who broke off a marriage engagement could be sued for breach of promise. Monetary damages included actual expenses incurred in preparing for the wedding, plus damages for emotional distress and loss of other marriage prospects. Damages were greatly increased if the woman—like half of engaged women between World War I and World War II—had engaged in sexual intercourse with her fiancé.Beginning in 1935, these laws were repealed or limited. However, the social and financial cost of a broken engagement was no less: marriage was the only financially sound option for most women, and if she was no longer a virgin, her prospects for a suitable future marriage were greatly decreased. The diamond engagement ring thus became a source of financial security for the womanengagement ringsengagement ringsengagement ringsengagement ringsengagement ringsengagement ringsengagement ringsengagement ringsengagement ringsengagement rings
