There is a common misconception that diamond engagement rings are an ancient tradition. It wasn’t until the De Beers diamond cartel decided to put millions into advertising campaigns that the diamond ring became embedded into the culture.
De Beers was founded in 1888 and were able to restrict the supply of diamonds on the market to raise the price far above what would have been market levels. They were able to do this by persuading the world’s diamond miners to market almost all diamonds through the De Beers Central Selling Organization (CSO). De Beers was successful in making diamonds appear rarer than they were, by aggressively restricting the supply of diamonds on the market.
De Beers marketed diamond engagement rings as a timeless symbol of love, introducing the phrase “a diamond is forever,” in 1947. In 1939, around 10% of engagement rings had diamonds and by 1990 80% of them did. The idea that a man should have to spend his annual income was also a suggestion from De Beers. It was later reduced to two months income. They advertised: “how else could two months’ salary last forever.”
Diamonds are only crystallised carbon, sapphires and rubies are actually more rare than diamonds are.