In 1866, a fifteen-year-old boy named Erasmus Jacobs spotted a strange pebble glinting on the banks of the Orange River in South Africa. He took it home, and his mother used it as a toy for the younger children. The stone passed from neighbor to neighbor until a mineralogist confirmed what no one had dared to expect: it was a rough diamond of 21. 25 carats.

The discovery ignited one of the most frantic mineral rushes in human history. Thousands of prospectors flooded the region, cities sprang up overnight, and men abandoned families and farms to dig for fortune with nothing but a pick and a prayer. By 1871, the rush centered on a hill called Colesberg Kopje, located on farmland owned by two brothers, Johannes and Diederik de Beer. The brothers were farmers with no interest in diamonds, so they sold their land cheaply and walked away from what would become one of the richest diamond deposits in the world.

The mine that bore their name would produce millions of carats, but the de Beers brothers saw almost none of that wealth. Their name, however, became synonymous with diamonds forever. Amid the chaos arrived an ailing eighteen-year-old Englishman named Cecil John Rhodes. He had come to South Africa in 1870 on medical advice, his weak chest supposedly helped by the dry African climate.

His brother Herbert already worked in a diamond mine, and Cecil joined him less out of ambition than because he had no better option. What set Rhodes apart from the thousands of diggers racing through the dust of Kimberley was not strength or mining experience, but his mind. While everyone else dug, Rhodes thought. He realized that diamonds, unlike gold, derive nearly all their value from perceived scarcity.

Gold has intrinsic industrial uses; diamond is essentially crystallized carbon, one of the most common elements on Earth. Its value lies only in what people believe about its rarity. That illusion was in real danger. Kimberley’s fields produced diamonds at such a rate that prices had fallen by roughly ninety percent from their 1869 peak.

The market was flooded, and every new stone reduced the value of all the others. Rhodes concluded that the only way to save the diamond was to control supply entirely. While other miners dug, Rhodes bought up prospecting rights. His first profitable venture was not mining at all but renting steam pumps to other miners who needed to drain their flooded claims.

He reinvested every penny into acquiring more rights. Rhodes needed enormous capital to consolidate the Kimberley mines, so he turned to powerful friends. He secured financial backing from the Rothschild family, specifically Nathaniel Mayer Rothschild and N M Rothschild & Sons of London. He also partnered with Alfred Beit, a German-born diamond magnate who shared his vision of consolidation.

Rhodes’s main rival was a flamboyant East London-born showman named Barney Barnato, who had arrived in Kimberley with nothing but a cheap cigarette box and a hustler’s instinct, and had fought his way to become one of the richest mine owners in the region, controlling the Kimberley Central Mining Company. What followed was one of the most dramatic business conflicts of the nineteenth century. Rhodes and Barnato engaged in a fierce bidding war for control of the Kimberley mines, buying each other’s shares, fighting proxy battles, and maneuvering behind the scenes for months. The final negotiations reportedly lasted over eighteen hours, and by the end, Barnato had lost.

In exchange for selling his company, he received a check for 5,338,650 pounds, the largest check ever written at that time. On March 12, 1888, De Beers Consolidated Mines Limited was born. Rhodes, aged thirty-five, now effectively controlled all diamond mines in South Africa, meaning the vast majority of the world’s supply. He moved quickly to establish the first pillar of his monopoly.

He negotiated with the London Diamond Syndicate, a group of accredited dealers who agreed to purchase fixed quantities at fixed prices. This arrangement ensured that only a limited number of stones reached the open market, regardless of how much was actually mined. Supply became detached from reality, existing on paper, in agreements, and in vaults. By the time Rhodes died in 1902 at forty-eight, De Beers controlled nearly ninety percent of the world’s rough diamond production.

Rhodes left behind a philosophy as much as a company: the only way to maintain the value of diamonds is complete, absolute, ruthless control of supply. His successor took that philosophy to its furthest extreme. Ernest Oppenheimer arrived in South Africa in 1902, the same year Rhodes died. A German immigrant sent to Kimberley as a clerk for the diamond brokering firm Dunkelsbuhler & Company, he was quiet, meticulous, and relentless.

Where others saw a settled industry, Oppenheimer saw gaps. In 1917, with financial backing from J. P. Morgan & Co.

, he founded his own mining company, Anglo American. Over the next decade, he systematically acquired diamond interests that De Beers had neglected, particularly in South West Africa, modern-day Namibia. He acquired alluvial deposits along the coast, secured mining rights on lands Germans had been forced to surrender after World War One, and built a strong position outside De Beers’s control entirely. Then he made a bold move: he began buying shares in De Beers itself.

By 1929, he had enough stock to assume the chairmanship. The timing was striking. He took the helm just as the Great Depression devastated the global economy. Diamond demand collapsed, sales fell to nearly zero, and by 1932 mining operations stopped altogether.

It was a disaster for the industry but a crucible for Oppenheimer, and through that crucible he built the most powerful commodity cartel the world has ever seen. He established a principle that would define the industry for generations. The only way to increase the value of diamonds, he believed, is to make them scarce, deliberately limiting the quantity that reaches the market. To execute this strategy, he created the Central Selling Organisation in 1934.

The CSO was stunning in its simplicity and devastating in its effectiveness. De Beers would buy rough diamonds from its own mines and from independent producers around the world. The stones were sent to London, sorted, graded, and packed into boxes. About ten times a year, a select group of roughly 100 to 150 pre-approved buyers, known as sight holders, were invited to De Beers offices on Charterhouse Street for what was called a sight.

Each buyer was presented with a box of diamonds. De Beers set the price and chose the contents, and the terms were non-negotiable. You accepted the box at De Beers’s price or you did not buy at all, and refusal risked never being invited back. There was no bargaining and no open market.

The true genius lay in the vaults. When demand weakened during recessions, oil crises, and periods of geopolitical instability, De Beers did not lower prices. It absorbed the excess supply. Unsold diamonds were simply stored in vaults in London and withheld from the market.

By the mid-1980s, the stockpile was estimated at over five billion dollars in rough diamonds, all piled up in the dark, unsold. The purpose was simply their absence from the market. For independent producers, the choice was clear. They could sell through the CSO at a guaranteed price to a guaranteed buyer, or they could try the open market knowing De Beers could flood it at any moment with billions in stockpiled stones, collapsing their prices overnight.

It was an offer that could not be refused, not because it was generous, but because the alternative was financial ruin. Between 1939 and 1989, the wholesale price of a flawless D-grade one-carat diamond rose roughly fifteen-fold, outpacing inflation and the stock market. Not because diamonds were becoming rarer, but because De Beers controlled the supply. Controlling supply, however, was only half the equation.

Demand had to be controlled too, and that required something more powerful than a vault full of gems: a story. In the late 1930s, the diamond industry faced a genuine crisis. The Depression had crushed luxury spending, and diamond engagement rings were far from mainstream culture in the United States, where they accounted for no more than ten percent of engagements. The stone was seen as a luxury for the rich, not a symbol of love for ordinary people.

In 1938, De Beers hired the advertising agency N. W. Ayer & Son. The solution was elegant, almost diabolical: do not sell diamonds, sell eternity.

N. W. Ayer did not run conventional advertisements. It launched a cultural movement.

It planted stories in newspapers and magazines about the magic of diamond rings, arranged for Hollywood starlets to wear diamonds at premieres, and ran a weekly syndicated service called Hollywood Personalities that supplied 125 leading newspapers with descriptions of diamonds worn by celebrities and the wives and daughters of political leaders. Then, in 1947, a young copywriter named Frances Gerety, working late at N. W. Ayer’s offices, scribbled four words on a piece of paper before going to sleep: diamonds are forever.

The slogan first appeared in a De Beers ad in 1948 and ran in every De Beers engagement advertisement afterward. In 1999, Advertising Age named it the slogan of the twentieth century, beating both Just do it and The pause that refreshes. Gerety herself never married and died single. But the slogan did essential economic work.

If diamonds are forever, they are never resold; they remain in the family, passed down through generations, never returning to the market. De Beers had effectively eliminated the secondary market. Every diamond sold was one permanently removed from circulation, kept in jewelry boxes and safety deposit boxes by owners raised to believe that selling a diamond is, in essence, selling love. In the 1980s, De Beers introduced another concept that became entrenched custom: the two-months’ salary rule.

It was invented by an advertising agency to increase the average purchase price, and it worked. In Japan, where diamond engagement rings had been nearly nonexistent before the 1960s, De Beers promoted a three-months’ salary rule. By 1981, sixty percent of Japanese brides received diamond engagement rings, up from almost nothing two decades earlier. Total annual De Beers sales of diamonds in the United States had been about 23 million dollars in 1939; by 1979, that figure had swelled to over 2.

1 billion dollars. Not because diamonds had become rarer or more useful, but because De Beers had rewritten the rules of desire. By the early 1990s, however, even the most fortified empire begins to show cracks. The first fracture came from Russia.

For decades, the Soviet Union had been one of the world’s largest diamond producers, and De Beers had quietly managed the threat with a secret agreement to buy almost all Soviet production and channel it through the CSO. When the Soviet Union collapsed in 1991, that arrangement collapsed with it. Russian diamonds began leaking onto the open market through unofficial channels, and dealers in Antwerp and Tel Aviv bought Russian stones at discounted prices, bypassing the De Beers system entirely. Then came Australia.

The Argyle mine in Western Australia, operated by Rio Tinto, began producing enormous quantities of diamonds in the mid-1980s. In 1996, Argyle broke away from the CSO entirely and began selling its diamonds independently, the first major producer to withdraw. Then came Canada. In the late 1990s, large diamond deposits were discovered in the Canadian Arctic, and companies like BHP Billiton and Rio Tinto developed mines entirely outside De Beers’s control.

They marketed their stones as ethically sourced conflict-free alternatives, in stark contrast to growing controversy over African diamonds. By the late 1990s, the term blood diamonds had entered the global lexicon. In countries like Sierra Leone, Angola, and the Democratic Republic of Congo, rebel groups seized diamond mines and used the profits to fund brutal civil wars. For a company that had built its wealth on buying diamonds from anyone who had them for sale, the blood diamond crisis was a public relations disaster.

De Beers had long acted as a buyer of last resort, absorbing stones from the African and Antwerp open markets regardless of origin, which meant that for years it had unknowingly or otherwise funnelled blood diamonds through its system. The global response was fierce. The United Nations issued resolutions, and human rights groups including Global Witness and Amnesty International campaigned directly against De Beers. The 2006 Leonardo DiCaprio film Blood Diamond brought the issue to millions.

De Beers stopped buying diamonds on the open market entirely and supported the creation of the Kimberley Process, an international certification scheme designed to prevent conflict diamonds from entering legitimate trade. It was necessary, but it cost the company dearly. By restricting itself to its own supply, De Beers voluntarily surrendered a large portion of the market it once monopolized. Its market share, which had ranged between eighty and ninety percent throughout most of the twentieth century, fell to about sixty-five percent by 2000, thirty-five percent by 2010, and roughly thirty percent by 2020.

The final blow came not from a competing mine or hostile government, but from a laboratory. Lab-grown diamond technology had existed since the 1950s, when General Electric first proved diamonds could be produced from carbon under extreme heat and pressure. But the process was too expensive and limited for commercial gem quality. That changed in the 2010s.

Two methods for producing high-quality lab diamonds, HPHT and chemical vapor deposition, improved dramatically in efficiency and cost. By the early 2020s, it became possible to produce lab diamonds indistinguishable from mined stones: the same crystal structure, the same hardness, the same brilliance. The only difference was that mined diamonds take billions of years to form; lab diamonds take a few weeks in a machine. The price difference was enormous.

Wholesale lab-grown diamond prices fell by nearly seventy-four percent between 2020 and 2025, and by 2025, finished lab-grown diamonds cost eighty to ninety percent less than their mined equivalents. For consumers, especially younger ones already skeptical of the industry’s marketing, the offer was irresistible. In 2018, lab-grown diamonds accounted for about two percent of engagement ring sales in the United States. By 2025, that figure exceeded forty-five percent.

De Beers’s response was one of the worst strategic errors in corporate history. In 2018, it launched Lightbox, a lab-grown jewelry brand priced at eight hundred dollars per carat, far below the market rate. The message was that lab-grown stones are cheap, disposable, and inferior to natural diamonds. But consumers did not see it that way.

They saw De Beers itself admitting that these stones were real diamonds, and they chose the cheaper option. By 2025, De Beers announced it would close Lightbox entirely. The financial consequences were severe. Anglo American, which owned eighty-five percent of De Beers, was forced to write down the company’s value for three consecutive years: 1.

6 billion dollars in 2023, 2. 9 billion in 2024, and 2. 3 billion in 2025, a total of 6. 8 billion dollars over three years.

De Beers’s market valuation fell from over nine billion dollars in 2023 to just 2. 3 billion by late 2025. The company recorded an EBITDA loss of 511 million dollars in 2025, and production fell by twenty-two percent. Anglo American’s chief executive publicly stated that the sale of its stake was in advanced negotiations, but finding a buyer for a company losing hundreds of millions annually, in a structurally disrupted sector, with Botswana’s government owning fifteen percent and demanding a majority stake, is difficult.

Some industry observers speculated the final sale price could be as low as one billion dollars. Botswana compounds the dilemma. It is the world’s largest diamond producer by value, supplying De Beers with about seventy percent of its rough diamonds through Debswana, a joint venture owned equally by the government and De Beers. Diamond revenues transformed Botswana from one of the poorest countries at independence in 1966 into one of Africa’s most stable and prosperous nations.

But the relationship has soured. President Mokgweetsi Masisi publicly demanded a much larger share, seeking roughly a fifty-fifty split. He threatened to walk away from the partnership entirely. A new ten-year agreement was eventually reached, but the negotiation revealed a fundamental shift in power.

De Beers was no longer the indispensable partner; it had become the more vulnerable party. Perhaps the most dangerous threat is generational. Millennials and Generation Z view diamonds through a completely different lens, raised in an age of transparency, instant information, and climate anxiety. They are aware of blood diamonds, environmental destruction from open-pit mining, and that the two-months’ salary rule was invented by an advertising agency.

Surveys suggest younger consumers are shifting spending toward gold and experiences. The same strategy that made De Beers invincible for a century, insisting that diamonds are rare, precious, and irreplaceable, is now being used against it. Lab-grown diamonds do not just offer a cheaper alternative; they expose the fundamental lie of the entire enterprise. If a diamond can be made in a machine in two weeks, identical in every measurable way to a stone that took billions of years to form, what exactly are you paying for when you buy a mined diamond?

You are paying for a story. A story written by an advertising agency in 1947. A story that, for the first time in over a century, is no longer convincing enough to justify its price. None of this means De Beers will vanish overnight.

It still operates some of the most productive diamond mines on Earth, including Jwaneng in Botswana, often described as the richest diamond mine in the world by value. There remains a strong market for natural diamonds, particularly at the elite level, among collectors and luxury consumers who value origin and rarity. Diamonds, regardless of how they are made, retain a deep emotional hold on global culture. A century of tradition cannot be undone in a decade.

But the monopoly is gone. The power to set prices is gone. The power to dictate terms to buyers, producers, and entire countries is gone. What remains is a company forced to compete on equal footing in a market whose foundations have been permanently changed by technology.

For more than a hundred years, a single private company persuaded billions of people that a geologically abundant stone was rare, that spending two months’ salary on it was tradition rather than marketing invention, and that selling it was emotionally improper. It did not sell a product; it built a cultural institution. It reshaped the way humans express love, while maintaining an absolute monopoly on the supply of the very product it had made indispensable. By any objective standard, that stands as one of the most audacious feats of market manipulation in the history of commerce.

But audacity has a lifespan. The company that wrote four words that changed the world, diamonds are forever, is learning that nothing lasts forever. Not monopolies, not myths, and not even diamonds, when a machine can make one in a few weeks at a fraction of the cost. If the value of a diamond was never in the stone itself but in the story told about it, the question now is what happens when that story stops working.

Empires built on manufactured desire can collapse as quickly as they were built. It only takes someone, or something, to reveal that the emperor was never wearing any clothes at all. In this case, the emperor never had diamonds; it only had a very good story.