A US-based startup, Marathon Fusionhas made headlines with a claim that seems plucked from ancient alchemy: turning mercury into gold. Using neutron radiation from nuclear fusion, the company says it can create gold-197, the stable isotope of gold, as a byproduct of clean energy generation.
According to the startup, their fusion reactors can bombard mercury with neutron particles, converting it into mercury-197. This isotope then decays into gold-197. In theory, a 1 GW thermal fusion plant could yield up to 5,000 kilograms of gold per year—worth more than $550 million at current prices.
The process was detailed in a paper that has not yet undergone peer review, meaning the scientific community has not formally verified the claims.
Marathon Fusion says the gold production won’t interfere with the reactor’s primary purpose: producing clean, limitless energy. If proven viable, this approach could make fusion more commercially attractive by turning reactors into multi-product industrial systems.
As the startup puts it, “The goal of classical alchemy is now achievable through practical engineered solutions.”
Despite the excitement, major hurdles remain. Different mercury isotopes could result in radioactive forms of gold. The startup’s Chief Technology Officer, Adam Rutkowski, admitted that some of the produced gold might need to be stored for 14–18 years before it becomes safe for use.
Additionally, the underlying fusion reactors themselves are still in developmental stages, meaning commercial-scale production is likely years away.
While scientists view nuclear fusion as the future of clean energy, this twist—producing valuable metals—could attract fresh funding and interest. Marathon Fusion has already raised $6 million in private funding and secured $4 million in government grants.
Still, until working fusion plants exist at scale, the dream of synthesizing gold from mercury may remain just that—a dream.
Marathon Fusion’s vision of gold-producing fusion reactors is bold and imaginative. Whether it’s the dawn of a new industrial era or just scientific hype will depend on further research, rigorous peer review, and real-world reactor results. For now, the world watches—and waits.