San Francisco-based fusion startup Marathon Fusion claims to have turned mercury into stable gold, potentially opening new possibilities for precious metal production. Founded in 2023 by Kyle Schiller and former SpaceX engineer Adam Rutkowski, the company says its result exceeded a record set by CERN by a factor of 10. The claim has not been independently verified.
A Fusion Company With Ambitious Backers
Marathon is developing fuel systems for future fusion power plants. It says it works with the U.S. Department of Energy and received a 2023 award from ARPA-E. Its backers include Bill Gates’ Breakthrough Energy and mining group Anglo American, which owns De Beers.
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How The Gold Claim Works
Marathon says neutrons from fusion reactions strike mercury, creating an unstable isotope that decays into gold. CERN’s Large Hadron Collider previously produced about 29 picograms of gold during experiments between 2015 and 2018, but the particles existed only briefly before being destroyed in collisions.
Marathon also says its plasma centrifuge has broken a 40-year-old Soviet record for separating isotopes used in fusion fuel. However, it has not disclosed how much gold it produced or the cost, and independent confirmation is still lacking.
Why The Diamond Comparison Matters
Lab-grown diamonds show how technological advances can reshape a precious-material market. As production scaled, wholesale prices fell, creating a cheaper alternative to mined stones.
De Beers launched its Lightbox lab-grown diamond brand in 2018 at $800 per carat but shut it down in 2025 to refocus on natural diamonds. The wider diamond sector has also faced financial pressure, with Anglo American reportedly exploring a sale of its stake in De Beers.
Gold Is A Different Market Entirely
Gold is deeply embedded in global finance. The World Gold Council says mines produced 3,672 tonnes in 2025, while total historical mined output reached about 222,600 tonnes. Central banks also hold gold as a reserve asset and have been buying heavily in recent years.
Gold traded at $4,062 an ounce on Thursday, below its January record high.
A 2025 Marathon study estimated that a fusion plant could produce around five tonnes of gold annually for every gigawatt of electricity generated. If 100 plants reached that output, they could add 500 tonnes a year, equivalent to roughly 14% of 2025 mine production.
That scenario remains theoretical: no fusion plant currently sells electricity, and commercial systems are still years away. Marathon also says the gold could contain radioactive isotopes and might need to be stored for up to 18 years before sale.
The Real Question For Investors
Marathon has not announced plans to commercialise the material. Still, its claim raises questions about whether commercially viable fusion could create new markets for materials traditionally valued for their scarcity.
Transmuted gold could eventually become indistinguishable from mined gold once its radioactivity fades. If gold can be manufactured at scale, the implications for a market built on scarcity could be significant.







