As climate change worsens, the transition from fossil fuels to clean energy sources becomes more urgent. However, many alternatives to fossil fuels have a dark side. The risks posed by nuclear reactors and mining lithium for batteries are familiar, but clean energy’s reliance on permanent magnets, and the rare earth elements that comprise them, is less familiar. Permanent magnets are used everywhere: cell phones, audio speakers, power tools, electric cars, and wind and hydroelectric power generators. Most permanent magnets are comprised of rare earth elements like neodymium, dysprosium and terbium. These elements aren’t household names, but our society is dependent on them. Unfortunately, mining and purifying these elements generates significant environmental damage. Additionally, decades of outsourcing have given China nearly complete control of the rare earth supply chain, adding geopolitical risk. And as the demand for electrification increases, so does the demand for rare earths. One intriguing new alternative to rare earth magnets can be made from scrap iron. A particular crystal structure of iron and nitrogen known as “alpha double prime iron nitride” has the potential to be the strongest commercially viable magnet ever made.