The key facts

  • Marathon Fusion claims it turned mercury into stable gold, beating CERN's record (29 picograms) tenfold; no independent verification yet
  • The gold market is far larger than the diamond market: 2025 production was 3,672 tonnes, with the price around $4,062 per ounce
  • By the company's own estimate, 100 fusion plants could produce ~500 tonnes of gold per year, but no commercial plants exist yet

The Startup's Claim

Marathon Fusion, a San Francisco-based fusion energy company, announced on Wednesday that last month it turned mercury into 'real, stable gold,' beating CERN's record tenfold. The claim has not yet been confirmed by independent experts, and the available data do not make it possible to establish how much gold was produced and at what cost. The company was founded in 2023 by Kyle Schiller and Adam Rutkowski, a former SpaceX engineer, and develops fuel systems for future fusion power plants. Among its partners is the US Department of Energy; in 2023 it received an award from the ARPA-E agency. Its investors include Bill Gates's Breakthrough Energy and the mining group Anglo American, which owns De Beers.

The Method and the Records

Marathon's method involves irradiating mercury with neutrons from fusion reactions: the metal turns into an unstable isotope that decays into gold. For comparison: in 2025, CERN reported that the Large Hadron Collider, over its 2015–2018 operation, produced about 29 picograms of gold — roughly 86 billion nuclei that existed for a fraction of a second. The company also claims it broke a 40-year-old Soviet record using its plasma centrifuge, which separates isotopes for fusion fuel, and is building a reactor in San Francisco for record power density.

The Diamond Lesson

Market concerns stem from the precedent of lab-grown diamonds, chemically identical to natural ones. According to analyst Paul Zimnisky, wholesale prices for grown stones have fallen 90–95% since 2015, which also pressured prices for mined diamonds. De Beers launched the Lightbox brand in 2018 at $800 per carat but shut it down in 2025. In 2025, De Beers recorded a underlying loss of $511 million, and Anglo American, according to Bloomberg, is in talks to sell an 85% stake for about $1 billion to a consortium led by former De Beers chief Gareth Penny; Richemont and Signet, according to media reports, may join the talks.

How Gold Is Different

The gold market is significantly larger: in 2025, 3,672 tonnes were mined, with about 222,600 tonnes mined in all of history (World Gold Council). Central banks, including China and Poland, are actively building up reserves. On Thursday, gold traded at $4,062 per ounce — more than 27% below the January record of $5,598. According to Marathon's own 2025 study, a fusion plant could produce about 5 tonnes of gold per year per gigawatt; 100 such plants would add ~500 tonnes per year, about 14% of last year's production. However, no fusion plant is yet selling electricity, and such gold may contain radioactive isotopes and require storage for up to 18 years. There are no public commercialization plans, but, unlike diamonds, transmuted gold, after the isotopes decay, will be indistinguishable from mined gold.