US startup claims it turned mercury into gold in lab using nuclear fusion

Marathon Fusion has claimed that it converted mercury into stable gold using fusion technology, but the quantity produced, production cost and commercial viability remain unclear

Marathon Fusion, a US-based startup, has claimed that it converted mercury into stable gold using nuclear fusion technology.

 

The San Francisco-based company said on Wednesday that it had achieved the conversion last month, claiming a production rate 10 times higher than a record set by CERN, the European particle physics laboratory. The company has not disclosed how much gold it produced or the cost of the process.

Last month, we demonstrated high-rate alchemy: turning mercury into real, stable gold, beating CERN’s record by a factor of 10. Last week, we enriched isotopes in the world’s most powerful plasma centrifuge, beating the Soviet record that stood for 40 years. Now, we’re building a fusion reactor in San Francisco to achieve record power density.

— Marathon Fusion (@MarathonFusion) October 21, 2026

How does the process work?

The company says it uses neutrons released during fusion reactions to bombard mercury. This converts the mercury into an unstable isotope, a form of the element that subsequently decays into gold.

 

 

The claim follows earlier experiments at CERN, where researchers used the Large Hadron Collider to produce gold nuclei during operations between 2015 and 2018. CERN reported in 2025 that the experiments had produced about 29 picograms of gold, or 29 trillionths of a gram. The gold nuclei existed for an extremely short time before being destroyed in collisions with the accelerator's equipment.

 

Marathon Fusion says its process has exceeded CERN's record by a factor of 10. 

Could lab-made gold lower prices?

The claim has drawn comparisons with lab-grown diamonds, whose wholesale prices have fallen by 90–95 per cent from their 2015 levels, according a report by Euronews. The availability of cheaper, laboratory-produced stones has also put pressure on prices of mined diamonds.

 

However, producing gold through fusion presents different challenges. The technology would depend on the development of commercial fusion power plants, which are not yet selling electricity. Gold produced through the process could also contain radioactive isotopes, potentially requiring storage for up to 18 years before it can be considered safe for commercial use, the report said.

 

Marathon Fusion estimates that a future fusion power plant could produce around five tonnes of gold annually for every gigawatt of electricity-generating capacity. If 100 such plants were operating, their combined output could reach about 500 tonnes a year, equivalent to roughly 14 per cent of the previous year's mined gold production, it claimed.