On the afternoon of June 27, 1966, a noise like a jet cracking through the sound barrier erupted suddenly above the town of Saint-Séverin, in southwestern France. Residents recalled “detonations and whistling sounds” as the source of the noise, a meteorite, streaked across the sky. Soon the giant space rock, dull gray and weighing 250 pounds, punched the earth, burying itself in the soil of a local walking path. It left an impact crater approximately two feet deep and two and a half-feet wide. Two days later, a team from France’s National Museum of Natural History arrived to take several small samples of the rock.
Meteorites, like the weighty one that slammed into Saint-Séverin, can contain precious metals and debris from the farthest reaches of our galaxy—geologic clues to how our own planet formed. Thousands of years ago, early societies valued meteorites for their high concentrations of nickel and iron, formed over millions of years as the rocks tumbled through the solar system. Civilizations as far back as 2500 B.C. used space metals to forge tools and weapons. Ancient Egyptians called meteoric metal “iron from the sky,” and perhaps the most famous example is the 13-inch-long iron dagger buried with the Egyptian pharaoh Tutankhamun in 1350 B.C.
The meteorite that landed in France, though, held something maybe even more valuable. Geologists examining those samples more than 20 years later made an exciting discovery: The ball of space rock that fell on Saint-Séverin contained a small amount of a rare metal, known as tetrataenite, that had only recently been identified. The specimen recovered from the meteorite was about 40 micrometers across, just the width of a human hair, but the metal could help revolutionize global production of electronics—everything from iPhones to fighter jets.
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The metal’s name comes from its form and makeup: Tetrataenite has a tetragonal structure composed of taenite, an alloy made when nickel combines with iron. It’s similar to the rare-earth metals needed to produce the strong magnets that power many of today’s consumer devices, electric vehicle batteries, military weapons, and hardware essential to renewable energy infrastructure.
“Rare earths are going into absolutely vital segments of industry and technology,” says Ariel Cohen, a senior research fellow at the Atlantic Council. “They’re key components for computing as well as all the new technology that fuels or supports the energy transition.”
But extracting these metals happens in only a few spots globally. The work is difficult, dangerous, and environmentally risky. And the country that controls 70 percent of the world’s production, China, has threatened to throttle back its supply of rare-earth metals during trade and military negotiations with the U.S. and other nations. Despite its immense promise, tetrataenite has been viewed as far too uncommon to be helpful—because it’s found exclusively in meteorites. Until last year, that is.
In fall 2022, Lindsay Greer, PhD, a professor of materials science at the University of Cambridge, England, and several colleagues announced that they had synthesized tetrataenite, heating commonly found minerals above their melting point (about 2,630 degrees Fahrenheit) to create the once-elusive metal. The lab-produced version has magnetic properties that are enticingly close to rare-earth minerals such as neodymium, praseodymium, and dysprosium. Magnetic tetrataenite could take their place, powering countless devices for decades to come.
Greer’s discovery comes at a crucial moment. The hankering for products that contain rare earths is only going up, which makes the group of 17 metallic elements some of the most sought-after resources on the planet. According to the U.S. Department of Energy, worldwide demand for rare earths is expected to increase by 400 percent over the next several decades.
“When you’re faced with a critical material problem, you can do one of two things: You can find more, or you can use less,” says Tom Lograsso, director of the Critical Materials Institute, a mineral research laboratory within the U.S. Department of Energy.
The sheer quantity of rare earths required for magnet production is staggering when put into raw numbers. For example, a Virginia-class nuclear-powered attack submarine requires 9,200 pounds of permanent magnets made with rare earths. (Permanent magnets are always magnetic, unlike electrical magnets that require an electrical charge to work.) And a proposal by the U.S. Departments of Energy and Interior to generate 86 gigawatts of offshore wind power by 2050 would require more than 17,000 tons of neodymium.
“The biggest worry for the magnet industry is supply risk,” says Greer. That makes his breakthrough—a powerful magnet that doesn’t rely on rare earths—a potential game changer.
Greer wasn’t initially interested in rare-earth substitutes. His research focuses on how metal materials change their structures, and he mainly studies alloys, including those made of iron and nickel. In late 2019, his team at Cambridge, working with colleagues from the Austrian Academy of Sciences, were investigating the mechanical properties of iron-nickel alloys containing small amounts of phosphorus. It was all rather auspicious—meteorites like the one that crashed in Saint-Séverin already contain iron, nickel, and phosphorus.
Hoping to make a metallic glass, which is an alloy of atoms jumbled together without a discrete shape, researchers on Greer’s team placed bits of iron, nickel, and a phosphide compound in a copper dish housed inside a simple electric furnace. It’s a miniature version of the larger industrial furnaces used for smelting iron: High-voltage electric currents pass across an arc suspended above the material generate intense, metal-melting heat. But when Greer’s team finished casting, they got an unexpected by-product. Examining his creation under a microscope, Greer was stunned to discover that the iron and nickel atoms were arranged in ordered, tetragonal shapes—just like the tetrataenite that came from meteorites.
“That was a surprise,” Greer says. “We were looking at this particular alloy with a completely different interest, with no focus on magnetism.” But after some research into tetrataenite, especially its magnetic properties, Greer and the others began to wonder how much of the valuable cosmic material they could produce. “It got us into the whole story of replacing rare earths,” he says.
Around the same time that Greer and his team made their announcement, engineers at Northeastern University in Boston revealed that they, too, had devised a means of producing tetrataenite. Their efforts are spearheaded by Laura Lewis, PhD, a professor of chemical engineering. Northeastern’s method is similar to Greer’s in that nickel and iron are heated in a furnace, with one exception: As the melt cools down, Lewis’s team applies “existential stress,” according to its patent, which involves bashing or milling the by-product to get the atoms inside to form those tetragonal shapes.
That could be an important step. For tetrataenite to perform as well as rare earths do, its structure must endure the stress involved in producing high-quality, strong magnets. Rare earths already do that supremely well, thanks to their unique makeup. Unlike most metals, rare earths have an additional layer of electrons called an F-electron shell, which most elements do not possess. That extra dose of electrons keeps a magnet from losing its magnetism as materials heat up. Manufacturers add rare-earth minerals such as neodymium and praseodymium to ensure that magnets maintain their polarity even at temperatures above 300 degrees. Dysprosium and terbium, two other rare earths, are sometimes mixed into magnets made for particularly demanding products, like wind turbines and U.S. submarines.
To boost the strength and resilience of a permanent magnet, manufacturers apply heat and pressure to powdered rare earths, essentially welding them together. That creates a bulk magnet, which is cooled and cut into various shapes. The finished magnets can be small slivers, no thicker than a dollar bill for an iPhone speaker, or formed into large wedges and sintered together to create the magnets used in wind turbines. Regardless of their shape and size, permanent magnets are everywhere. The photos from your iPhone camera? The music in your AirPods? Neither are possible without rare-earth magnets. And each F-35 stealth fighter contains 920 pounds of rare-earth magnets, which are used to control its weapons systems, radar, and rudders.
If you dissected the motor of an electric vehicle, you would find permanent magnets—each made with a pinch of neodymium and praseodymium—arranged around a copper coil that winds around a central drive shaft. Stomping on the gas sends an electric current through the coil, creating a magnetic field with the opposite polarity of the magnets. The opposing forces make the coil spin quickly, turning the drive shaft, which makes the wheels go round. Rare-earth magnets excel at this transfer of energy from mechanical to electrical and back again. With one pound of permanent magnets, and an electric charge no greater than the one running an iPad, the Tesla Model Y can rip from a dead stop to 60 miles per hour in under four seconds. That power has the world clamoring for rare-earth minerals and their super-magnetic properties.
In just the past decade, demand for rare earths has skyrocketed. The need for dysprosium alone will increase by more than 2,500 percent by 2035, according to analysts at the University of Pennsylvania’s Kleinman Center for Energy Policy. Mined production of rare earths has also increased dramatically. In 2010, the world dug up 133,000 tons of rare-earth materials; in 2022, that number exceeded 300,000 tons, worth $9.5 billion. By 2028, the trade in rare earths is expected to be worth $21 billion.
Supplies of rare-earth minerals are getting ever tighter. China is reportedly exploring limiting the amount of the crucial materials it exports to American defense contractors. Without a breakthrough in manufacturing, or the discovery of additional sources of rare earths, a synthetic material like tetrataenite could be our best bet for keeping important weapons, green technologies, and beloved electronics operating into the future.
While China dominates rare-earth mining, the U.S. has one lone operational mine. Nestled deep in California’s Clark Mountain Range, about 200 miles southeast of Los Angeles, the massive open-pit Mountain Pass mine is nearly the length of nine football fields. And if you planted the Washington Monument at the mine’s deepest point, the rust-colored, human-made canyon would still eclipse the 555-foot-tall obelisk by about 50 feet.
For about 20 years beginning in the mid-1960s, the U.S. led the world in rare-earth mining. That changed in the 1980s, when China ramped up its mining efforts. Blessed with rich deposits of rare earths, the country cornered the market by mining the metals more cheaply (mainly by paying workers low wages) and selling them at rock-bottom prices. Its lackadaisical approach to environmental regulation also gave it a leg up. Last year, Chinese mines produced 210,000 tons of rare earths, nearly 70 percent of the world’s supply. Mines in the U.S. struggled to keep pace, closing one by one until only the largest operation, Mountain Pass, remained. But it too shuttered for a time, following a toxic waste spill in 2002.
Environmental degradation comes with the territory. Mining is destructive on its own, but rare earths must also be chemically separated from the larger mineral deposits—a messy and potentially hazardous process. In huge open-pit mines like Mountain Pass, excavators dig earthen benches into the ground that allow miners to access lower elevations. There, miners drill holes, pack them with explosives, and blast open the rock to extract dense rare-earth oxide ore. Humongous dump trucks carry the ore to milling machines that crush and grind the ore into sandlike granules. Even in this form, the granules still contain unwanted minerals. At on-site chemical plants, the granulated ore is coated with chemicals or compounds to create a reaction and then placed in “froth flotation” tanks, where the rare earths rise to the surface and are skimmed off the top. The solids left behind are removed from the slurry, and the water is recycled back to the flotation process.
The problem is even worse in China, where environmental standards are lower. The Bayan-Obo district in Inner Mongolia contains the world’s largest rare-earth mine and the world’s largest tailings pond, which has been filled with toxic chemicals since the 1950s. The health consequences are startling. According to Chinese state media reports, the pond was never properly lined and the poisonous water is seeping into the ground, destroying nearby crops, killing livestock, and making its way to the Yellow River, a vital source of drinking water in the region.
Globally, no rare-earth mine operates without doing some harm to its workers and the environment. The commonly cited figure is that mining just one ton of rare-earth elements results in 2,000 tons of tailings waste in the form of toxic dust, separation chemicals, wastewater, and radioactive residue.
In the U.S., Mountain Pass has an improving environmental record. After the 2002 spill that closed operations, the mine changed hands several times. In 2017, MP Materials, a public company headquartered in Las Vegas, assumed ownership and revived mining operations. Among other changes, it implemented a process to recycle the toxic wastewater needed to process rare earths, which it believes will reduce the chance of another environmental disaster.
Production at the mine is increasing too. Five years ago, Mountain Pass produced 14,000 tons, or 8 percent, of the world’s rare earths; last year, that number rose to 42,000 tons, or 14 percent. Still, demand outpaces those increases in mining production. In the U.S., high costs and strict regulations prevent new mines from opening. And deep concerns exist over the environmental destruction caused by rare-earth mines in China and elsewhere.
“It’s beyond just scarcity,” Northeastern’s Lewis said last fall. “Because the methods necessary to process the ore that comes out of the earth are really environmentally hazardous—I would say even damaging.”
Tetrataenite can mitigate those issues. Its base metals, iron and nickel, are two of the most abundant metals on earth. They’re the standard elements in stainless steel, for example. Both are cheaper and easier to extract from the earth than rare earths, with less severe environmental repercussions.
Tetrataenite might also allow producers to bypass a crucial processing stage required to purify the metals after they’re separated from other minerals at the mine. That step is done almost entirely in China, which controls 87 percent of worldwide rare-earth processing. China so dominates the mining and processing of rare earths that in 2018, the U.S. Congress ordered the Pentagon to stop purchasing neodymium magnets made in China. Last year, several U.S. senators proposed further legislation that would prevent any defense contractors from sourcing any rare earths from China by 2026.
“If we are in a confrontation with Beijing, they can stop the supply,” says the Atlantic Council’s Ariel Cohen, who notes that the U.S. currently imports 95 percent of its rare-earth compounds and magnets. “The whole supply chain has to be beefed up in the U.S.,” he says. “So if overall the process [for tetrataenite] is economical and safer or environmentally better, then why not?”
Underscoring the stakes, the U.S. Department of Defense gave Mountain Pass a $35 million grant in 2022 so that it could begin processing rare earths in California, bypassing China completely. That’s in addition to $9.6 million the Pentagon provided in 2020 to bolster the mine’s output. MP Materials is also constructing a manufacturing facility in Fort Worth, Texas, that it says will churn out enough permanent magnets laden with rare earths by 2025 to power 500,000 electric vehicle motors—a quantity that could power every new electric vehicle bought in the country.
Much more still needs to be done to meet the growing demand in the U.S. and globally. Patents in hand, the teams led by Greer and Lewis are working to turn their breakthroughs into meaningful amounts of mass-produced tetrataenite. It won’t be easy. The best either team can do now is produce trace amounts, which still need to be fully verified, inside their small laboratories. Next, they must develop a manufacturing process capable of making tetrataenite consistently and at scale. Greer acknowledges that they are likely years away. “Our ongoing research has shown how difficult it is to make tetrataenite,” he says.
One of their biggest obstacles is finding a way to deal with temperatures. At temperatures above several hundred degrees, iron and nickel atoms like to move around. (This is what lent meteoric iron its malleability, making it popular among earlier societies and dagger-wielding Egyptian pharaohs.) But as alloys of iron and nickel cool down, the atoms inside become less mobile, and therefore less likely to arrange themselves into the tetragonal structure that creates magnetic tetrataenite. Manufacturing the material on a large scale will require researchers to dramatically speed up how atoms of iron and nickel arrange themselves into that stable tetragonal structure and remain locked in place as the metals cool to ambient temperatures.
That’s only half the challenge. Permanent magnets made of rare earths must withstand high temperatures, sometimes above 300 degrees Fahrenheit in electric-vehicle motors, for instance. But heating tetrataenite to those levels breaks down the bonds between atoms, collapsing the tetragonal structure that gives the material its impressive magnetic properties.
“The real challenge is not in making the tetragonal or getting the atoms arranged the way you want them, but keeping them in that state while you go about working in the real world,” Lograsso says.
Should either research team successfully clear those hurdles, it would be a monumental breakthrough—one that could reorder the global supply chain. Countries without their own deposits of rare earths could more readily source materials to power computers, electric vehicles, wind turbines, and military tech. It would be a boon to the green-energy movement, while slowing the environmental harm created by rare-earth mining and processing.
Whether tetrataenite could be that hero material remains an open question. But if we can harness the magic of meteorites, we may find that expanding the pool of permanent magnets comes not from digging larger mines, but from a space metal produced right here on Earth.
Andrew Zaleski, a writer based near Washington, D.C., covers science, technology, and business.