Marathon Fusion, a San Francisco-based fusion energy company, said on Wednesday that it converted mercury into stable gold last month and claimed to have beaten CERN’s previous record by a factor of ten. The claim has not been independently verified, and the company has not disclosed how much gold was produced or what it cost.
CERN produced roughly 29 picograms of gold in 2025 during Large Hadron Collider operations in 2015 to 2018, equivalent to about 86 billion gold nuclei. Marathon’s method fires neutrons from fusion reactions at mercury, turning it into an unstable isotope that decays into gold.
Scale against the mining industry
Gold mines produced 3,672 tonnes in 2025, according to the World Gold Council. Marathon’s own 2025 study estimated a fusion plant per gigawatt could yield about 5 tonnes a year, so 100 such plants would produce around 500 tonnes, roughly 14 percent of last year’s mine output.
Gold was trading at $4,016.51 an ounce in our market data as of 07:36 GMT, its lowest in 31 days and more than 27 percent below its January record high of $5,598, a figure from the record.
Caveats on storage and power
Converted gold may need up to 18 years of storage before sale and may contain radioactive isotopes. No fusion plant currently sells electricity.
Source: Marathon Fusion | Data: LBMA
