Light Rare Earth Elements (LREE)

The light rare earth elements (LREEs) are the more abundant half of the rare earth family, and they make up most of the tonnage that rare earth mines produce. Two of them, neodymium and praseodymium, go into the permanent magnets in electric vehicle motors and wind turbines. Lanthanum and cerium, the most plentiful, come out of the same ore in larger amounts than the market can use. That mismatch shapes the economics of light rare earth mining.

Which elements REEx counts as light rare earths

In its guide to rare earth minerals, REEx groups lanthanum through europium, plus scandium, as light rare earths. That covers lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium and scandium. The heavy rare earths run from gadolinium through lutetium, plus yttrium.

Promethium belongs to the group on paper only. It is so rare and unstable in nature that USGS Professional Paper 1802-O leaves it out of its discussion of rare earth deposits.

Why other lists draw the line in a different place

USGS Professional Paper 1802-O uses the traditional split by atomic weight. It counts lanthanum through gadolinium as light, so europium and gadolinium both fall on the light side. It puts terbium through lutetium, plus yttrium, in the heavy group, and it does not list scandium among the rare earths at all.

The USGS 2026 chapter on heavy rare earths starts at terbium and runs through lutetium. It treats yttrium as heavy but reports it separately, and it does not name gadolinium.

Policy documents add a third layer. Law firm Holland & Knight described China's April 2025 export rules as covering "medium and heavy" rare earth materials, a list that includes samarium and scandium. When a report says "light" or "heavy," check which list it uses before comparing figures.

The abundant half of the family

Heavy rare earths are less abundant than light ones, according to USGS. Its average crustal abundances put cerium at 66.5 parts per million, neodymium at 41.5 and lanthanum at 39. Europium is the scarce exception, at 2.0 parts per million.

The ores differ too. Carbonatites, igneous rocks rich in carbonate minerals, have been the world's main source of light rare earths since the 1960s, according to USGS Professional Paper 1802-O. Deposits where bastnaesite is the main ore mineral are strongly enriched in light rare earths. Mountain Pass in California, Bayan Obo in China and Mount Weld in Western Australia are all carbonatite deposits. Monazite is the other major source. It is the main rare earth mineral in beach and river sands, and it contains radioactive thorium. Heavy rare earths, by contrast, come mainly from ion-adsorption clays in southern China and Myanmar.

Magnets carry the group's value

Neodymium and praseodymium drive the light rare earth market. They go into neodymium-iron-boron (NdFeB) magnets, and they are usually separated and sold together as NdPr oxide, according to a 2022 U.S. Department of Energy supply chain review. Magnets were the leading global use of rare earths in 2025, according to the USGS 2026 rare earths chapter. Samarium supplies a second magnet type, samarium-cobalt. It keeps working at higher temperatures than neodymium magnets (Arnold Magnetic Technologies). Lynas lists aerospace among samarium's uses (Lynas).

Lanthanum goes into oil refinery catalysts and optical glass (USGS Professional Paper 1802-O). Nickel-metal hydride batteries, used in some hybrid vehicles, have anodes made of a lanthanum-based alloy (USGS Professional Paper 1802-O). Cerium's main uses are glass polishing, catalysts and glassmaking, according to a 2018 review. Europium is used in the red phosphors of lamps and displays (RSC). USGS reported that scandium's main uses in 2025 were aerospace alloys and solid oxide fuel cells.

The cerium and lanthanum surplus

Ore does not come in the proportions buyers want. Researchers call this the balance problem. A 2015 review by Koen Binnemans and Peter Tom Jones found that the light rare earth market was driven by neodymium demand for magnets. Because neodymium makes up a fairly small share of light rare earth ores, meeting that demand left cerium and samarium in surplus. The 2018 follow-up listed lanthanum, cerium, samarium and gadolinium among the rare earths available in excess.

The same 2015 review noted that the lanthanum and cerium in Western miners' ore often lower the value of their output. For a light rare earth miner, that puts the weight on NdPr content rather than total tonnage. The review called for new high-volume uses for cerium and lanthanum, such as removing phosphate from water.

Where light rare earths are mined and separated

China mined about 270,000 of the world's estimated 390,000 metric tons of rare earth oxide in 2025, according to USGS. The ore then has to be separated into individual elements, and China's lead is wider at that stage of the rare earth supply chain.

The IEA reported in October 2025 that China accounted for about 91% of separation and refining of the magnet rare earths and 94% of sintered magnet production. That figure covers neodymium and praseodymium, plus the heavy rare earths dysprosium and terbium. It does not cover lanthanum, cerium, samarium, europium or scandium, and REEx found no comparable global figure for them.

As of October 2026, plants separating light rare earths outside China include:

• Malaysia. Lynas separates NdPr from Mount Weld ore at its Malaysian plant (Lynas, July 2026). The company reported its first samarium oxide there in March 2026 (Lynas).
• United States. MP Materials produces NdPr oxide at Mountain Pass, California, along with cerium and lanthanum products, according to its 2025 annual report.
• Estonia. Neo's Silmet plant in Sillamäe separates rare earths, including NdPr oxide, the company said in 2022 (Neo).
• France. Solvay said it began commercial production of rare earths for permanent magnets at La Rochelle in April 2025 (Solvay). The line separates neodymium and praseodymium (Le Journal des Entreprises).

Scandium follows a different path. The USGS scandium chapter reported that it was produced only as a byproduct in 2025. China, the leading producer, has recovered it from titanium, zirconium, rare earth and iron ore processing.

Export controls on light rare earths (as of October 2026)

On April 4, 2025, China placed seven rare earths under export licensing in MOFCOM Announcement No. 18. Two of them, samarium and scandium, are light rare earths under the REEx split. The rule also covers neodymium magnet materials that contain dysprosium or terbium. Lanthanum, cerium, praseodymium and neodymium were not on the list.

In October 2025, China added europium and four heavy rare earths to its controls. It then suspended that rule in November 2025 before it took effect (IEA; CIRS). Under MOFCOM Announcement No. 70, the suspension was set to end on November 10, 2026. As of early October 2026, China had not announced an extension of that suspension. The April controls on samarium and scandium were never suspended and remained in force, according to Tech Times.

What drives light rare earth demand and supply

Demand for the group follows magnet demand, led by electric vehicle motors and wind generators. Supply of the whole group rises and falls with NdPr demand, because cerium and lanthanum come out of the same ore whether anyone needs them or not. In the United States, only limited quantities of rare earths were recovered from batteries, permanent magnets and fluorescent lamps in 2025, according to USGS.

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