for men under the name "mangagement rings". Industry 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. 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 traditionally wear engagement rings, women also occasionally present their partners with an engagement gift. Like all jewellery, the price for an engagement ring varies considerably depending 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, and emeralds have different systems. The jewellery may be chosen to honor a family tradition, to use family heirlooms, to have an unusual style, to have socially responsible characteristics (e.g., a style that is not associated with blood diamond controversy or the pollution caused by gold mining and cyanide process), to fit the individual's stylistic preferences, or to manage cost. Synthetic diamonds and diamond substitutes such as cubic zirconias and moissanites are also popular choices that are socially responsible and 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 mid-20th century in an effort to increase the sale of diamonds. In the 1930s, they suggested that a man should spend the equivalent of one month's income in the engagement ring. In the 1980s, they suggested that he should spend two months' income on it (three months in Japan). In 2012, the average cost of an engagement ring in the US as reported by the industry was US$4,000. In a 2015 scholarly study, almost a quarter of couples said that they did not buy a ring, and another third spent less than US$2000 on it. Less than 15% of couples spent $4,000 or more. In the UK, estimates of the average cost of an engagement ring range from £1200 to £2000. Scholarly research indicates that expensive engagement rings are associated with early