Why diamonds became the symbol of eternal love

In 1888, companies competing at the diamond mines of Kimberley, South Africa, merged into one and became De Beers. But bringing the mines together did not make diamonds sell well. A diamond was just one of many gemstones.

In 1938, De Beers teamed up with an American advertising agency to advertise diamonds. Within three years, diamond sales in the United States rose by more than half.

In 1947, De Beers introduced the slogan "A Diamond is Forever". It likened the diamond, said to be the hardest and rarest thing in the world, to a love that no hardship can break. The advertising trade publication Ad Age later named it the best advertising slogan of the 20th century.

The idea that an engagement ring means a diamond took hold in the United States and spread around the world. In the 40 years after the advertising began, De Beers' diamond sales in the United States grew nearly a hundredfold.

De Beers opened mines across Africa. In the 1980s, nearly nine in ten of the world's rough diamonds were sold through De Beers. Since De Beers decided how many to release, De Beers also controlled the price.

From the 1990s on, new mines opened in Russia and Canada. In 1996, Australia's Argyle mine, then the world's largest, ended its sales contract with De Beers. The company was indicted on price-fixing charges in the United States and faced a monopoly investigation in Europe. It was also criticized for links to diamonds from conflict zones in Africa.

The monopoly fell, but De Beers is still the world's second largest. It mines a little over one in five of the world's rough diamonds. It is reshaping itself by cutting costs, making its management more transparent, and focusing on sustainability.

A diamond is forever.
Through one well-written slogan, De Beers not only changed its own fate but changed wedding culture around the world.