De Beers' century‑long grip on diamond supply revealed

For more than a hundred years the De Beers consortium engineered a tightly controlled diamond market. By fixing purchase volumes with the London Diamond Syndicate in 1889 and later regulating output during the early 1890s, the company created the illusion of scarcity. A landmark advertising campaign launched in 1938, featuring the slogan “A Diamond is Forever,” linked diamonds to everlasting love and drove demand for engagement rings that had previously been uncommon.

The monopoly persisted through the 20th century under the Oppenheimer family, using stockpiling and selective dumping to keep prices high. Recent challenges have arisen from new mining sources in Russia, Canada, Australia, Botswana and South Africa, as well as the rise of lab‑grown diamonds, which have eroded De Beers’ market share and prompted legal scrutiny of its anti‑competitive practices.

The analysis shows that the perceived rarity of natural diamonds is largely a product of sustained marketing and supply manipulation rather than geological scarcity.