Prior to the 20th century, engagement rings were strictly luxury items, and they rarely contained diamonds. But in 1939, the De Beers diamond company changed all of that when it hired ad agency N.W. Ayer & Son. The industry had taken a nosedive in the 1870s, after massive diamond deposits were discovered in South Africa. But the ad agency came to the rescue by introducing the diamond engagement ring and quietly spreading the trend through fashion magazines. The rings didn’t become de rigueur for marriage proposals until 1948, when the company launched the crafty “A Diamond is Forever” ring.jpgcampaign. By sentimentalizing the gems, De Beers ensured that people wouldn’t resell them, allowing the company to retain control of the market. In 1999, De Beers chairman Nicky Oppenheimer confessed, “Diamonds are intrinsically worthless, except for the deep psychological need they fill.”
In addition to diamond engagement rings, De Beers also promoted surprise proposals. The company learned that when women were involved in the selection process, they picked cheaper rings. By encouraging surprise proposals, De Beers shifted the purchasing power to men, the less-cautious spenders.