Rare earth minerals: bastnasite, monazite, xenotime and clays
By RareMetals.net Editorial Team · Published
Rare earth elements are not found as pure metals. They occur in a few hundred minerals, but almost all production comes from four ore types: bastnasite, monazite, xenotime and ion-adsorption clays. Which one a mine works decides which rare earths it can sell: bastnasite and monazite are rich in the light rare earths used in magnets, while xenotime and the clays supply most of the heavy rare earths such as dysprosium and terbium.
The main rare earth minerals
| Mineral | Formula (simplified) | Rare earth content | Main rare earths | Where it is mined |
|---|---|---|---|---|
| Bastnasite | (Ce,La,Nd)CO₃F | About 70-75% rare earth oxide | Light: cerium, lanthanum, neodymium, praseodymium | Bayan Obo (China), Mountain Pass (California), Sichuan (China) |
| Monazite | (Ce,La,Nd,Th)PO₄ | About 55-65% rare earth oxide; contains thorium | Light, with some samarium, gadolinium and yttrium | Mineral sands (Australia, India, Brazil, southeastern US), Mount Weld (Australia), Bayan Obo |
| Xenotime | YPO₄ | About 55-65% rare earth oxide, mostly yttrium | Heavy: yttrium, dysprosium, terbium, erbium, ytterbium | Malaysian tin tailings, mineral sands, Browns Range (Australia) |
| Ion-adsorption clays | Rare earth ions held on clay minerals | Very low grade, often 0.05-0.2% rare earth oxide | Heavy and medium: yttrium, dysprosium, terbium, europium | Southern China, northern Burma (Kachin State), Brazil, Chile |
| Loparite | (Ce,Na,Ca)(Ti,Nb)O₃ | About 30% rare earth oxide | Light, with niobium and titanium | Lovozero (Russia) |
| Eudialyte | Complex zirconium silicate | A few percent rare earth oxide | Relatively rich in heavy rare earths | Greenland, Canada, Sweden (development projects) |
Bastnasite
Bastnasite is a rare earth fluorocarbonate and the world’s largest source of light rare earths. China’s Bayan Obo deposit in Inner Mongolia, mined mainly for iron, is the single biggest rare earth source, and California’s Mountain Pass, operated by MP Materials, is a bastnasite carbonatite. Bastnasite contains little thorium, which makes it easier to process than monazite, but it is poor in heavy rare earths: Mountain Pass ore contains only about 0.12% yttrium among its rare earths (USGS).
Monazite
Monazite is a rare earth phosphate found in granites and, most usefully, concentrated in heavy-mineral sands along with ilmenite, rutile and zircon. Before the 1960s it was the main rare earth source. Its drawback is thorium, typically several percent, which makes the waste radioactive and the processing licences harder to get. The US produced monazite from heavy-mineral sands in the southeast in 2025, and Lynas’ Mount Weld deposit in Western Australia is a weathered carbonatite rich in monazite (USGS).
Xenotime
Xenotime is an yttrium phosphate that carries most of the heavy rare earths. It occurs in mineral sands, in tin-mining tailings in Malaysia, and in a few hard-rock deposits such as Browns Range in Western Australia. It is one of the few hard-rock sources of dysprosium and terbium outside China.
Ion-adsorption clays
In southern China and northern Burma, deep tropical weathering of granite has left rare earth ions loosely attached to clay. The grade is very low, but the rare earths can be leached with a simple salt solution, without crushing or acid cracking, and the ore is rich in heavy rare earths. These clays supply most of the world’s dysprosium and terbium. Leaching has caused serious soil and water pollution, and production in Burma’s Kachin State has been disrupted by conflict.
New ionic clay projects are being developed in Brazil and Chile. A Brazilian mine producing ionic-clay concentrate with elevated terbium and dysprosium received a $465 million US DFC loan in November 2025 (USGS).
Other sources
Rare earths can also be recovered from apatite in phosphate rock and iron ores (Sweden’s LKAB is studying this), from coal ash, from uranium and tin tailings, and from recycled magnets. Scandium is a separate case: it is recovered as a by-product of nickel, titanium and aluminum processing rather than from rare earth minerals.
From mineral to metal
Mining is only the start. Ore is concentrated, the mineral is cracked with acid or alkali, and the mixed rare earths are separated into individual elements by hundreds of solvent-extraction stages. Most of that separation capacity is in China. See rare earth reserves and production by country for the supply chain and the guide to the 17 rare earth metals for what each element is used for.
Rare earth minerals FAQ
What are the top 3 rare earth minerals?
Bastnasite, monazite and xenotime. Together with ion-adsorption clays, which are not a single mineral, they supply almost all rare earth production.
Which mineral has the most rare earths?
By content, bastnasite (about 70-75% rare earth oxide in pure mineral). By value, the clays and xenotime matter most because they carry the expensive heavy rare earths.
Is monazite radioactive?
Mildly, because it contains thorium (and some uranium). That is why monazite processing needs radiation licences and careful waste management.
Where are rare earth minerals found in the United States?
Bastnasite at Mountain Pass, California; monazite in heavy-mineral sands in the southeast; and deposits under study in Wyoming (Bear Lodge), Alaska (Bokan Mountain), Texas (Round Top) and elsewhere.
Are rare earth minerals valuable to collectors?
Specimens of bastnasite, monazite or xenotime are sold to mineral collectors, but their value depends on crystal quality, not rare earth content.
Sources: USGS Mineral Commodity Summaries 2026; mineralogical reference data. General information only.