Marathon Fusion claims to turn mercury into stable gold, surpassing CERN's record

San Francisco startup Marathon Fusion announced on X on October 21 that it turned mercury into "real, stable gold," claiming to beat CERN's record by a factor of 10. However, the demonstration lacked details on production volume or experimental data; CERN's ALICE team measured about 29 picograms of gold from its 2015 to 2018 run. Marathon's 2025 paper modeled about 2 tonnes of gold per gigawatt of thermal power annually, compared to global mine production of 3,672 tonnes in 2025, and 222,600 tonnes of existing above-ground mined gold as of Q2 2026. Furthermore, the startup's current reactor is only 1 kilowatt of fusion power, a millionth of a gigawatt, and the freshly made gold would require 7 to 17 years of storage before sale due to radioactive isotopes.