In 1947, the De Beers Group, a British diamond company, handed the world four words: “A diamond is forever.” With these words, they pulled off the impressive trick of persuading generations of lovers that a big, shiny rock was the most respectable proof of devotion. The slogan worked so well that few buyers thought to ask where the stone had been before it reached the jeweler’s case—a question the diamond industry has never been eager to answer.

Consider what a diamond actually is. Lab-grown and natural diamonds are built from the same carbon atoms in the same crystal structure, making them “chemically, physically, and optically identical.” Even seasoned gemologists need specialized equipment to spot the difference. Nothing the eye or hand can detect separates the two, so the real difference lies in the journey each takes to reach the display cases.

The lab-grown journey is the simpler one. These stones are grown in controlled laboratories rather than dug from the earth, and their production generally leaves a lighter carbon footprint. A lab-grown stone has no chain of custody running through a war zone, and grading labs such as the Geminological Institute of America (GIA) and International Gemological Institute (IGI) note on each report that the diamond was made in a laboratory.

For mined diamonds, the journey can be brutal. A common type of natural diamonds, called conflict diamonds, come out of war zones and bankroll armed groups. They frequently rely on forced labor, often that of children. Militias have kept control of mining regions through brutality, pressuring civilians to work under threat of death, and laborers in affected areas still endure dangerous conditions with little to no pay and non-existent labor rights to protect them. The damage extends to the land as well. Mining can strip forests, erode soil and poison water supplies with toxic chemicals, while abandoned pits can become breeding grounds for disease or sites of drowning. Buyers who recoil at this history are reassured that an international system exists to keep such stones out of the market.

That system is the Kimberley Process, established in 2003 to certify rough diamonds as conflict-free, but its definition is narrow and its enforcement is riddled with loopholes. Since a diamond is certified by the country that last exported it, a stone smuggled out of one nation can be certified as ethical by another. For example, in 2008, Zimbabwe’s army took over the Marange diamond field and killed more than 200 people, including miners and residents. Yet, the country’s gems still count as conflict-free under the KP’s definition. Russia, whose state-owned Alrosa company faces U.S. sanctions for helping fund the invasion of Ukraine, remains a KP participant. A label that survives both a massacre and a war of aggression is a marketing convenience, not a moral guarantee.

That certainty is exactly what mined stones cannot offer. Fairness requires acknowledging that not every mined diamond is a blood diamond. Côte D’Ivoire, which was torn apart by a diamond-funded civil war, now directs its diamonds toward peaceful economic development. But that is precisely the difficulty for a conscientious shopper, because when certification can be evaded and origins obscured, no one can be certain which kind of stone rests on the finger. The moral burden lands on the buyer, who is asked to trust a system with documented gaps.

Defenders of natural stones point to rarity and ancient origins, and the appeal is easy to understand: a gem that took billions of years to form underground feels like a gift from nature rather than a product, and thus some buyers place symbolic weight on it. I would not dismiss that feeling, but diamond rarity differs greatly from what marketing suggests. De Beers spent much of the last century controlling how many diamonds reached the market to manipulate supply and demand. Scarcity was always manufactured, and it is a strange virtue to prize a stone because fewer people can own it, especially when others paid for it with their safety and their land.

“A diamond is forever” was a brilliant line, but the sentiment makes a poor substitute for a clear conscience. When an identical stone exists without the bloodshed, the scarred landscapes or the lingering doubt about its origins, choosing the mined one is no longer tradition but a decision. An ethical buyer should make the right one.