The world runs on rock · Story 4 of 12

The Magnet the invisible muscle in every motor

Electric cars, wind turbines, phones, drones and hard drives all turn electricity into motion with small, ferociously strong magnets. Nearly all of them are made of neodymium, iron and boron, and nearly all of them are made in China.

Scroll to open a motor

Take it apart

A motor is a spinning magnet

Electric vehicle charging bays painted on a car park, with a white car plugged in

Charging bays at NASA's Kennedy Space Center, 2022. NASA/Kim Shiflett (public domain).

Open the aluminium case of an electric car's motor and there are two parts: the stator, which stays still, and the rotor, which spins inside it.

The stator

A stack of thin sheets of silicon steel, each a ring with teeth, wound with copper. Current flowing through the coils makes a magnetic field that sweeps round and round.

Housing aluminium, to carry heat away
Stator silicon-steel sheets, thin so less energy is lost as heat
Windings copper

The rotor

Magnets that chase the field

Set into the rotor are blocks of neodymium-iron-boron, the strongest permanent magnets made. They are pulled along by the stator's turning field, and the rotor spins with them. Without them, the motor would need more copper and more power to make the same field.

NdPrFeBDyTbCuAl

How much

The IEA counts about 0.5 kg of rare earths in a typical electric car, and 239 kg in every megawatt of offshore wind, where large turbines often drive their generators straight from the blades with big rings of magnets. An onshore megawatt needs about 14 kg.¹

False-colour satellite image of the Bayan Obo mine in Inner Mongolia: dark open pits and tailings ponds in pale desert — Bayan Obo (Baiyun Ebo), Inner Mongolia, seen by the ASTER instrument on NASA's Terra satellite. NASA/GSFC/METI/ERSDAC/JAROS and the U.S./Japan ASTER Science Team (public domain).

Where it starts

One mine in Inner Mongolia

Bayan Obo, north of Baotou, is an iron mine that also holds the world's largest known rare-earth deposit. NASA described it in 2012 as the site of almost half the world's rare-earth production.² China as a whole mined 69% of the world's rare earths in 2025.³

Inside the magnet

Millions of tiny magnets, lined up

A sintered magnet is pressed from powder into a block of tiny crystal grains. Each grain is a little magnet of its own. At the factory a strong pulse of field swings them all to point the same way, and the block becomes one magnet.

The crystal

Nd₂Fe₁₄B

Two atoms of neodymium, fourteen of iron and one of boron. Iron carries most of the magnetism; neodymium locks it along one direction so it can't easily be flipped. General Motors and Sumitomo Special Metals developed the material independently in 1984.⁴

The heat problem

Dysprosium at the edges

Neodymium magnets weaken as they warm, and a car motor runs hot. Adding the heavy rare earths dysprosium and terbium lets special grades work at up to about 200°C.⁵ Makers now put them where they do most good: along the grain edges.

Follow the supply

1 · Mining

China 69%, the United States 13%, Australia 7.4% and Myanmar 5.6% of 2025 mine output.³ For the rare earths used in magnets, the IEA puts China's share of mining at 60% in 2024.⁶

Satellite image of the Mountain Pass mine in the desert mountains of California

Mountain Pass, California, the United States' rare-earth mine, from NASA's Terra satellite (public domain).

2 · Separating

Rare earths come out of the ground mixed together and are among the hardest elements to separate. China did 91% of the world's refining in 2024.⁶ Australia's Lynas separates its own ore in Malaysia; most of the rest is separated in China.

3 · Making magnets

In 2005 China made about half the world's sintered permanent magnets. By 2024 its share was 94%.⁶ From there they ship to motor and car plants everywhere.

4 · The pinch point

One country mines most of the ore, separates almost all of it and makes almost all the magnets. That is why a licence form in Beijing can stop a car plant in Chicago.

September 2010

The first warning

After Japan detained a Chinese trawler captain near disputed islands, Japanese traders reported that rare-earth shipments from China had stopped. Beijing denied any ban, and the captain was released on 24 September.⁷

2009 to 2011

Prices go vertical

China had been cutting its export quotas. The monthly average price of dysprosium oxide rose from $91 to $2,377 a kilogram between January 2009 and August 2011, about 26 times.⁸ The line on the left is drawn on a log scale; on an ordinary one it would leave the screen.

Then

Prices fell back as buyers cut their use. The US, the EU and Japan took the quotas to the World Trade Organization, which ruled against them in 2014, and China dropped them.¹³ But the lesson stuck: whole industries rested on one supplier.

The lines show the size of each reported move, not a full price history.

4 April 2025

Licences for seven rare earths

China began requiring export licences for seven medium and heavy rare earths, among them dysprosium and terbium, and for magnets containing them.⁹ Shipments slowed while exporters waited for approvals.

May 2025

A car plant stops

Ford idled its Explorer factory in Chicago for a week for lack of rare-earth parts. Its chief executive said supply was "day to day", with licence applications "being approved one at a time".¹⁰

October and November 2025

On 9 October China announced wider controls, including on foreign-made products containing Chinese rare earths. After the Trump-Xi meeting it suspended those October measures until 10 November 2026; the April licences still apply.¹¹

Sep 2010Shipments to Japan reported halted.
Apr 2025Licences for seven rare earths and magnets.
Jul 2025The US Defense Department sets a $110/kg price floor for NdPr from Mountain Pass.¹²
Nov 2025October's wider rules paused for a year.

Silhouette of an early two-bladed wind turbine on a lattice tower against an orange sunset — The NASA-designed Mod-0A wind turbine on Block Island, Rhode Island, 1979. NASA Glenn Research Center (public domain).

Fifty years on

Bigger blades, bigger magnets

NASA and the US government built this 200-kilowatt turbine in the 1970s. Today's offshore turbines are many times larger, and many carry rings of rare-earth magnets in their generators: in the IEA's figures, 239 kg of rare earths per megawatt.¹

Why "critical"

Small amounts, no easy substitute

An electric car holds about half a kilogram of rare earths, but nothing else matches their magnets' strength for their size. That puts neodymium, praseodymium, dysprosium and terbium on the critical lists of the US, the EU, Japan and others.

NdRare earthsChina 69% DyDysprosiumheavy rare earth FeIronabout 72% of the magnet CuCopperChile 23% SiSiliconelectrical steel AlAluminiummotor housing CoCobaltsamarium-cobalt magnets NiNickelmagnet plating

Next in the series: The Rocket, the metals that survive launch. Before this: The Battery, The Mind and The Chip.

Sources

Shares of world output are from USGS Mineral Commodity Summaries 2026 via our minerals data; other figures are cited where they appear. The 3D models are illustrations, not engineering drawings; the price lines show reported moves, not price histories. Photos: NASA, public domain.