Magrathea Metals

Magrathea Metals is a privately held U.S. critical-minerals technology company headquartered in Oakland, California. Founded in 2022 by chemical engineers Alex Grant and Jacob Brown, Magrathea develops a next-generation electrolytic process to produce primary magnesium metal from seawater and waste brines, offering a carbon-neutral alternative to China-dominated supply. The company operates a pilot facility in Oakland running its proprietary magnesium chloride electrolyzer and plans a demonstration plant in Utah targeting roughly 1,000 tonnes per year, scaling toward 50,000 tonnes annually. Magrathea raised a $24 million Series A in 2026 co-led by Resource Technology Capital and Balerion Space Ventures, with backers including Capricorn Investment Group and VoLo Earth, and has attracted U.S. Department of Defense interest given magnesium’s importance to lightweight automotive and defense applications. With about 85% of global magnesium produced in China, Magrathea positions itself as a domestic, low-carbon supplier of this critical structural metal.