Light vs Heavy Rare Earths
Facts checked against sources on . How we check facts.
Light rare earths are the lower-atomic-number elements, led by lanthanum, cerium, praseodymium and neodymium, and heavy rare earths are the higher ones, starting around terbium and dysprosium and ending with lutetium, plus yttrium. The boundary is a convention, not a law of chemistry, and sources disagree on where gadolinium, samarium, europium and scandium belong. The distinction matters because heavy rare earths are less abundant, far more expensive and almost entirely refined in China.
$1,010 vs $69
average 2025 prices per kilogram: terbium oxide against neodymium-praseodymium oxide
over 99%
of refined dysprosium and terbium production in recent years was in China
Source: Adamas Intelligence
100%
US net import reliance for heavy rare earth compounds and metals in 2025
Source: USGS rare earths (heavy)
62 t
dysprosium and terbium produced by Lynas, the only commercial producer outside China by its own account, in the year to June 2026, summed from its four quarterly figures
Source: Lynas quarterly reports
Where is the line between light and heavy?
The line differs by source, and the table shows the main conventions. All agree that lanthanum, cerium, praseodymium and neodymium are light and that terbium to lutetium are heavy. The disagreement is about samarium, europium, gadolinium, scandium and yttrium.
| Source | Light | Heavy | Notes |
|---|---|---|---|
| USGS fact sheet (2002) | La to Eu | Gd to Lu, and Y | Says La, Ce, Pr and Nd make up 80% to 99% of most deposits |
| USGS Mineral Commodity Summaries 2026 | Not itemised | Tb, Dy, Ho, Er, Tm, Yb, Lu; Y is considered heavy but reported separately | Gadolinium is not in the heavy chapter |
| Congressional Research Service (2026) | La, Ce, Pr, Nd, Pm, Sm, Eu, Gd | Tb to Lu, plus Sc and Y | Notes that some classifications exclude Sc |
| EU Critical Raw Materials Act | Listed as "light rare earth elements" | Listed as "heavy rare earth elements" | Annex I separately names Nd, Pr, Tb, Dy, Gd, Sm and Ce as magnet rare earths |
| China, April 2025 controls | Not named | Described by press as "medium and heavy": Sm, Gd, Tb, Dy, Lu, Sc, Y | Licensing, not a formal group definition |
Sources: USGS Fact Sheet 087-02, USGS 2026 heavy rare earths, CRS IF13171, Regulation (EU) 2024/1252, USGS 2026 rare earths.
Why are heavy rare earths more valuable?
Heavy rare earths are more valuable because they are scarcer in ores, harder to source and needed for performance that cheaper elements cannot give. The USGS says heavy rare earths are less abundant than light rare earths but elevated in some ores, including ion-adsorption clays, and that light rare earths can substitute for heavy ones in several applications. The price gap in 2025 was large: terbium oxide averaged $1,010 per kilogram and dysprosium oxide $239, against $73 for neodymium oxide and $1.00 for lanthanum oxide. Terbium therefore cost about 15 times neodymium-praseodymium oxide on the USGS figures. See the element-by-element table.
Who supplies the heavy elements?
China supplies nearly all refined heavy rare earths, and outside China only a few small operations exist. Adamas Intelligence says China produced over 99% of refined dysprosium and terbium in recent years. The USGS reports that at least five companies were developing commercial-scale heavy rare earth processing in 2025 but that none produced sustained commercial quantities. Lynas produced 62 t of dysprosium and terbium in the year to June 2026, 19 t of it in the June quarter, and first produced samarium oxide in March 2026, with first-step capacity of about 400 t a year according to its March quarterly report. A mine in Brazil produces mixed concentrates from ionic clays with elevated terbium and dysprosium, and the US International Development Finance Corporation approved a $465 million loan to its owner in November 2025. In August 2025 the Department of War lent $150 million to MP Materials for a heavy rare earth separation facility at Mountain Pass. More on the separation capacity page.
What did China's controls change?
China's April 2025 licensing covered terbium, dysprosium, lutetium, samarium, gadolinium, scandium and yttrium, which are mostly the heavy and medium elements. The October 2025 expansion, which reached the remaining heavy elements, was suspended in November for a year. The Adamas outlook says prices outside China spiked several times higher after the April controls. See the export controls tracker.
Frequently asked questions
What is the difference between light and heavy rare earths?
Light rare earths are the lower-atomic-number elements, mainly lanthanum, cerium, praseodymium and neodymium, and heavy rare earths are the higher ones from terbium to lutetium plus yttrium. Heavy rare earths are less abundant, much more expensive and almost entirely refined in China.
Is neodymium a light or heavy rare earth?
Neodymium is a light rare earth. It, with praseodymium, makes up the bulk of magnet rare earth demand, while dysprosium and terbium, which are heavy, are added in smaller amounts for high-temperature performance.
Is gadolinium a light or heavy rare earth?
Gadolinium is classed differently by different sources. The Congressional Research Service lists it as light, the 2002 USGS fact sheet lists it as heavy, and China licensed it in April 2025 with the "medium and heavy" group.
Why are heavy rare earths harder to get outside China?
Heavy rare earths are harder to get outside China because they are scarce in most ores and the separation capacity for them is almost entirely in China. The USGS reports that no company produced sustained commercial quantities outside China in 2025.
Sources
Read on October 12, 2026. Figures on this page come from these documents; where a number is an estimate, the source says so.
- USGS Mineral Commodity Summaries 2026: Rare earths (heavy)
- USGS Mineral Commodity Summaries 2026: Rare earths
- USGS Fact Sheet 087-02: Rare earth elements, critical resources for high technology
- Congressional Research Service: Rare Earth Elements and U.S. Supply Chains (IF13171, 12 June 2026)
- Adamas Intelligence: Rare Earth Magnet Market Outlook, top predictions for 2026
- Lynas Rare Earths: 2026 Annual Report and Appendix 4E (26 August 2026). Lynas figures read on 14 October 2026
- Lynas Rare Earths: Quarterly report for the period ended 30 June 2026 (22 July 2026). Read on 14 October 2026
- Lynas Rare Earths: Quarterly report for the period ended 31 March 2026. Still the source for the first-step samarium capacity
- Regulation (EU) 2024/1252, Annexes I and II
