Perspective: Rock of Ages

The result of the trip would be one of the most successful advertising slogans ever created.

Ayer worked the account for a decade—draping diamonds on Hollywood starlets, mostly—but struggled to find a tagline. Then in 1947, a young copywriter named Frances Gerety chanced upon a photo of two newlyweds on their honeymoon and scribbled “A Diamond Is Forever” along the bottom. De Beers adopted the tagline the following year. The 1957 ad below is a classic early example of its use, and as the ad opposite demonstrates, the company has employed the phrase ever since (having added a “because”).

Of course, kings and maharajas had made diamonds desirable for centuries. The genius of what Gerety did was to fuse together the idea of swooning, everlasting love with a sparkly rock. According to psychologist Robert Passikoff, who runs the consultancy Brand Keys, “people take certain signs of objects and imbue them with an unspoken meaning”—and thanks to De Beers, diamonds have come to be seen as a natural rarity, a precious embodiment of the marital pledge. In the early days, not all grooms (who make up 90 percent of diamond buyers) got it, and so the copy helped things along with lines like “Your engagement diamond, with noble fire, reflects the greatness of your love.”

Eventually, the dudes glommed on—and they haven’t forgotten. While both the 2011 ad and its 1957 forerunner use beautiful diamonds as a thematic centerpiece, the contemporary ad has dispensed with all explanatory copy. “Over time,” Passikoff says, “consumers have a stronger perception of what the diamond represents, so you don’t need the copy. The meaning has endured. Why screw with success?”

But the strongest proof of the efficacy of “Diamonds Are Forever” isn’t measured in the endurance of the phrase, but its ability to cloud the heads of grooms-to-be (who drop an average of $3,200 on an engagement ring) with a sweet-smelling, fictional mist. Not only are diamonds not rare (De Beers holds back so much supply that if all the world’s diamonds were dumped onto the market, they’d be worth less than $30 each), but what they symbolize isn’t forever, either. According to the National Center for Health Statistics 43 percent of new marriages will end in the first 10 years.

So maybe diamonds aren’t forever—but a good slogan sure is.