Critical minerals are not a single chemical family. They are minerals, elements, substances, or materials considered critical because they are essential to an economy or national security and their supply chains are vulnerable to disruption. In the U.S. definition, the material must be essential, supply-risk exposed, and necessary for making products whose absence would have serious consequences. EU and IEA sources use the same basic idea: high strategic/economic importance plus high supply risk. Because “critical” is a policy-and-supply-chain label, the exact list can change by country and over time.
A useful plain-English definition is this: a critical mineral is a material modern society really needs, but cannot reliably or easily secure. That is why lithium, nickel, cobalt, graphite, copper, aluminum, silicon, and rare earth elements matter so much for batteries, power grids, electronics, defense systems, wind turbines, and EV motors.
One important detail:
a periodic-table picture is only a partial shorthand for critical minerals, because some critical-mineral commodities are not single elements. USGS notes that materials such as graphite, barite, phosphate rock, potash, fluorspar, and metallurgical coal are also treated as critical commodities on policy lists.
Rare earth elements (REEs) are a subset of the broader critical-minerals discussion, not the same thing. They are commonly treated as 17 elements: scandium, yttrium, and the 15 lanthanides. Despite the name, USGS describes rare earths as relatively abundant; the real challenge is finding them concentrated enough to mine and process economically.
Common rare-earth uses
- Magnets and electric motors: Neodymium (Nd) and praseodymium (Pr) are central to very strong permanent magnets; dysprosium (Dy) and samarium (Sm) help magnets keep performance, especially at higher temperatures. These magnets are used in EV motors, wind turbines, hard drives, speakers, and compact electric machines.
- Catalysts and petroleum refining: Lanthanum (La) and cerium (Ce) are widely used in refinery catalysts, and cerium is also used in catalytic systems such as automotive catalytic converters.
- Displays, lighting, and phosphors: Europium (Eu), terbium (Tb), and yttrium (Y) are important in red, green, and blue phosphors used in displays, fluorescent lighting, and related optical applications.
- Glass, optics, lasers, and fiber optics: Lanthanum improves optical glass and camera lenses; neodymium, erbium (Er), ytterbium (Yb), holmium (Ho), and thulium (Tm) are used in lasers, infrared optics, fiber optics, and portable X-ray systems.
- Medical and nuclear uses: Gadolinium (Gd) is used as an MRI contrast agent; lutetium (Lu) is used in PET detector applications; samarium, dysprosium, and holmium also appear in nuclear control, shielding, or reactor-related uses.
- Batteries, ceramics, and alloys: Lanthanum is used in nickel-metal hydride batteries; yttrium is used in ceramics and alloys; scandium (Sc) is valuable in superalloys and lightweight aerospace components.
A memorable example from USGS:
one wind-turbine magnet can require about 300 kilograms of neodymium.
