Rare earth elements (REEs) are a family of 17 metallic elements that play key roles in modern technology and industry. They include the 15 lanthanides (lanthanum through lutetium) plus two other elements, scandium and yttrium. What they are
- The 17 elements: scandium (Sc), yttrium (Y), and the 15 lanthanides: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu) .
Why they’re important
- REEs have unique magnetic, luminescent, and electrochemical properties that enable a wide range of applications, including permanent magnets for electric motors and wind turbines, phosphors for displays and lighting, catalysts, and various high-tech components in electronics and communications [WEB1].
- Demand is driven by sectors such as smartphones, data centers, renewable energy technologies, automotive and industrial tooling, and defense systems. Secure and resilient supply chains for these elements are a growing policy focus worldwide [WEB4].
Key characteristics
- Scarcity vs abundance: REEs are relatively abundant in the Earth's crust, but they are usually dispersed and seldom found in concentrated, economically extractable deposits. Purifying and separating them is technically challenging and costly, which affects supply security and pricing [WEB2].
- Occurrence and distribution: They are typically found together in mineral-bearing rocks and mineral concentrates; individual elements require complex processing to separate into usable forms [WEB2].
- Classification: The group is often discussed as 15 lanthanides plus scandium and yttrium. In some contexts, the lanthanides are referred to as rare-earth metals, even though their overall crustal abundance can be relatively high for certain members of the group [WEB2][WEB9].
Common applications by element type
- Light rare earths (e.g., cerium, lanthanum, praseodymium, neodymium, europium, samarium) are widely used in catalysts, polishing powders, glass & ceramics, and magnets in some contexts.
- Heavy rare earths (e.g., dysprosium, terbium, holmium, erbium, ytterbium, lutetium) are particularly important for high-performance magnets, specialized electronics, lasers, and fiber optics [WEB2][WEB9].
- Scandium and yttrium, while not always classified as lanthanides, are included in the REE group due to their similar chemical properties and widespread industrial roles (e.g., scandium in aerospace alloys and lighting, yttrium in phosphors and high-temperature superconductors) [WEB2][WEB8].
Notes and cautions
- Terminology: “rare earths” is a historical term and does not imply rareness; most REEs are relatively abundant, but their dispersed occurrence and the complexity of extraction and separation make supply chains sensitive to geopolitical and mining dynamics [WEB2][WEB4].
- Critical minerals context: REEs are often discussed alongside other critical minerals because of their economic importance and strategic value, though countries may define “critical” differently depending on policy aims [WEB2].
If you’d like, I can tailor this to a particular use case (e.g., magnet materials, consumer electronics, or policy implications) and provide a concise table of which REEs are most critical for those applications.
