# Armstrong Cites Bitcoin’s 21 Million Cap After Fusion Gold Claim By Simon Yoon Canonical URL: https://www.tokenpost.com/news/technology/44831 Published: 2026-10-30T15:33:05.000Z Updated: 2026-10-30T15:33:05.000Z Section: Technology > Marathon Fusion disclosed no experimental yield or definition for its claim that production was 10 times a CERN benchmark. Coinbase CEO Brian Armstrong invoked Bitcoin’s 21 million coin cap after Marathon Fusion claimed it produced stable gold from mercury, refocusing attention on the contrast between Bitcoin’s fixed issuance and gold’s potential supply growth. Marathon Fusion said in an Oct. 22 post that a September experiment used fusion-generated neutrons to make stable gold from mercury at a rate 10 times a CERN benchmark. The company disclosed no amount produced. Its [gold-from-mercury claim]() also did not define what the comparison measures. Armstrong made the Bitcoin comparison in an Oct. 26 post: “You can’t invent anything that will increase Bitcoin supply. There will only ever be 21M.” Bitcoin’s current protocol rules cap issuance at 21 million coins. New Bitcoin enters circulation through block rewards, which are cut in half every 210,000 blocks. The comparison turns on how each asset’s supply might change. Gold output could grow if a new production method became affordable at scale, while Bitcoin’s 21 million coin ceiling is set by its protocol rules. A separate 2025 simulation estimated that a specially designed fusion plant could produce about two metric tons of gold per gigawatt of thermal power each year. The model assumed mercury enriched to 90 atomic percent mercury-198; it does not describe the September experiment. At that modeled rate, one hypothetical plant would produce about 0.05% of the estimated 3,671.6 metric tons of gold mined in 2025. The CERN comparison involves a different process. Collisions at the Large Hadron Collider produced about 29 picograms of gold nuclei across four major experiments from 2015 to 2018; the nuclei fragmented almost immediately. Marathon Fusion has not specified whether its “10 times” figure compares mass, production rate or another measure. Fabian Schär, a professor of distributed ledger technology and fintech at the University of Basel, described the supply question as hypothetical: “Under the hypothetical assumption of inexpensive production at scale, gold would be no exception.” Any effect on gold supply would depend on production becoming inexpensive and large enough to reach the market. Marathon Fusion’s claim does not establish commercial output or a change in Bitcoin demand or either asset’s price. ## Links in this article - [gold-from-mercury claim](https://www.tokenpost.com/news/technology/38276)