The Diamond Engagement Ring Tradition Was Built by an Ad Campaign

Somewhere tonight, someone is working out how many months of pay a ring should cost. The number feels inherited, like a law nobody voted for. The rule has a birthday, and it is not very old. 1

In 1938, with diamond prices falling around the world, De Beers hired the New York advertising agency N.W. Ayer. The United States was already the market that mattered: about three quarters of the cartel's diamonds were being sold there for engagement rings, most of them small stones at an average of $80 apiece, and the agency's job was to persuade Americans to buy bigger and more expensive ones. 2

In 1947, a copywriter at that agency, Frances Gerety, wrote the line the campaign would run on: "A Diamond Is Forever." She never married. 3 The word "forever" was doing commercial work. A diamond that is never resold cannot undercut the price, and a stone kept in a family does not come back onto the market to compete with the next one De Beers sells. 4

The agency put diamonds on movie stars and into high school lectures. Its 1947 strategy plan described the goal plainly, to make the diamond engagement ring "a psychological necessity." 2 It worked. On the eve of the Second World War, about one engagement ring in ten contained a diamond. By the end of the century, about eight in ten did. 1

The price rule came from the same campaign. One month's salary was the suggestion in the 1930s. By the 1980s in the United States it was two, with ads asking, "How can you make two months' salary last forever?" 1 Japan had no diamond engagement custom at all. When the campaign arrived in 1967, under five percent of engaged Japanese women had a diamond ring. By 1981, sixty percent did. 2

The ring is real, and the wish to mark a promise with something is older than any of this. What has a birthday is the default, and the number attached to it. Two months of your pay was a sales target before it was ever a rule about love.