De Beers popularized the slogan “A Diamond Is Forever.” The phrase was created in 1947 by copywriter Frances Gerety for the N.W. Ayer advertising agency, which handled De Beers’ United States campaign.
The slogan linked diamonds with lasting love and marriage. It also helped reinforce the idea that engagement rings should contain diamonds, a custom that De Beers had strongly promoted through advertising since the 1930s.
The wording became one of the best-known advertising lines of the 20th century. It is sometimes mistakenly credited directly to De Beers, although the phrase was written by Gerety for the company’s campaign.
The slogan also appeared in the James Bond film title “Diamonds Are Forever,” released in 1971. The film’s title used a closely related phrase, not the exact advertising line.