"A Diamond is Forever" is one of the most recognized and effective slogans in advertising history. Diamonds are not the rarest gems (that honor goes to rubies), but they are the hardest. In 1938, De Beers hired ad agency N.W. Ayer & Son. The agency recommended a campaign that created the illusion of a diamond's scarcity and its association with romance. It changed everything. Since then, diamonds have become the de rigueur standard for engagement rings.
Ayer's marketing plan included advertising, PR, product placement in film, television and radio, as well as photographs of celebrities in magazines and newspapers. The specific goal was simple: Convey the idea that diamonds were eternal, forever linked with romance, emotionally valued, and a necessary luxury.
The enduring tagline was created in 1947 by N.W. Ayer copywriter Frances Gerety. At the end of a long day, she scrawled "a diamond is forever" on a picture of two honeymooning lovers. She placed it in her desk drawer and didn't look at it for several days. If the line still resonated when she revisited it, she believed it would be powerful. She was right. Another example of Elemental Thinking.
Here's some copy for a print ad that featured an illustration by Salvador Dali.
"And what of Love? There are girls' hearts and boys' hearts, speaking to each other daily above the trials and insecurity of our small universe. In the light of her engagement diamond, a girl's eyes keep a constant vigil . . . seeing recorded not only the loveliness of love but the the hope of a future tender and rewarding, when growing trust and abiding peace will give their world rich meaning."