Rare earth minerals

Rare earth minerals in the US: bastnaesite, monazite, xenotime and allanite

Four minerals carry the rare earths in US deposits, bastnaesite, monazite, xenotime and allanite, and only the first two supply rare earths in the US today. Bastnaesite is mined at Mountain Pass in California, and monazite is produced from heavy-mineral-sand concentrates in the southeast (USGS).

9 of the 14 tracked US sites name at least one of them, and the USGS describes 13 more districts that carry them. The mineral sets the process: bastnaesite and monazite are proven at commercial scale, while allanite and yttrofluorite are not (OSTI).

Verified through Oct 1, 2026

See the table All rare earth mines

Main minerals: 4Plus yttrofluorite at Round Top
Produced in the US today: 2Bastnaesite and monazite (USGS)
Tracked sites naming one: 9Of 14 on the map
USGS districts naming one: 13On the historic deposits page
US output, 2025: 51,000 tRare earth oxide in concentrate (USGS)

The definition

What counts as a rare earth mineral?

A rare earth mineral is a mineral in which rare earth elements are a main part of the chemical formula, so that a deposit can be mined for them. This page covers the four that the USGS counts among the main rare earth minerals in the US, plus the yttrofluorite named at Round Top.

The four: Bastnaesite, monazite, xenotime and allanite, which tracked US projects name and the USGS counts among the main ones in the US.
Added: Yttrofluorite, because Round Top, a tracked project, is described by it.
Left out: Euxenite, samarskite and thorite, which appear only in USGS-described districts and veins, and the many minor minerals of old deposits.
Matching: A project is listed under a mineral when its deposit description names it. The match is computed from the profiles, not typed here.

The comparison

Which rare earth minerals are in US deposits, and which projects name each?

Five minerals appear in the US projects tracked here. The table sets out each one's formula, what it carries, thorium, processing maturity and the projects and USGS districts that name it. Only bastnaesite and monazite supply rare earths in the US today.

Rare earth minerals in US deposits: what each carries, thorium, processing maturity and the US projects and USGS districts that name it
Mineral	Rare earths it carries	Thorium	Processing	Tracked US projects	USGS-described districts
BastnaesiteRare earth fluorocarbonate(Ce,La,Y)CO₃FRare earth oxide: 70% to 74%	Mostly light rare earths. Mountain Pass oxide is 82.7% lanthanum and cerium and 16.4% NdPr, with 0.0% dysprosium and terbium (OSTI).	Low. The USGS lists 0 to 0.3% thorium oxide and 0.09% uranium oxide for bastnaesite, and names monazite as the thorium-heavy mineral.	Proven at commercial scaleFroth flotation makes a concentrate of about 60% TREO. Mountain Pass roasts it at about 600 °C and leaches it in cold hydrochloric acid.OSTI: recovery from bastnaesite has been demonstrated on a commercial scale.	US supply today: Mined as a primary product at Mountain Pass, California (USGS 2026).Mountain Pass ProducingBear Lodge DevelopmentElk Creek DevelopmentBokan Mountain ExplorationSheep Creek Exploration	Wet Mountains, Gallinas Mountains
MonaziteRare earth and thorium phosphate(Ce,La,Y,Th)PO₄Rare earth oxide: 35% to 71%	Light rare earths with some heavy ones. The USGS says monazite typically holds 60% to 62% total rare earth oxide; concentrates from sands are typically 20% to 24% NdPr oxide, 1% to 3% dysprosium oxide and 0.3% to 1% terbium oxide (OSTI).	Yes. The USGS lists up to 20% thorium oxide and up to 16% uranium oxide, and says tighter rules on radioactive minerals drove many monazite sources out of the market in the 1980s.	Proven at commercial scaleA heavy mineral, concentrated from sand by gravity, magnetic and electrostatic separation to 50% to 60% or more TREO. White Mesa Mill cracks it with caustic soda and leaches it with hydrochloric acid.OSTI: recovery from monazite has been demonstrated on a commercial scale.	US supply today: Produced from heavy-mineral-sand concentrates in the southeastern US (USGS 2026) and processed at White Mesa Mill in Utah.Elk Creek DevelopmentBokan Mountain ExplorationSheep Creek ExplorationWhite Mesa Mill Plant operating	Wet Mountains, Idaho monazite placers, Hicks Dome, Pea Ridge, El Porvenir, Petaca district, Carolina monazite placers, Florida and Georgia beach placers
XenotimeYttrium phosphateYPO₄Rare earth oxide: 52% to 67%	Yttrium and heavy rare earths. The USGS says deposits enriched in heavy rare earths most commonly have xenotime as the principal rare earth mineral.	Uranium rather than thorium: the USGS lists 0 to 5% uranium oxide and gives no thorium figure.	Demonstrated to some extentUsually recovered with other minerals. In Florida, yttrium-rich xenotime is in the monazite concentrates from the sand operations (USGS).OSTI: recovery from xenotime has been demonstrated on a commercial scale to some extent.	US supply today: No primary US production; yttrium-rich xenotime occurs in the monazite concentrates produced in Florida (USGS 2026).Round Top DevelopmentBokan Mountain Exploration	Music Valley, Pea Ridge, Laughlin Peak
AllaniteRare earth silicate (epidote group)Ca(Ce,La,Y,Ca)Al₂(Fe²⁺,Fe³⁺)(SiO₄)(Si₂O₇)O(OH)Rare earth oxide: 3% to 51%	Cerium, lanthanum and yttrium in a silicate.	Some. The USGS lists 0 to 3% thorium oxide and says allanite grains are commonly damaged by its radioactive decay. La Paz is reported to be low in thorium and uranium (company-reported).	Needs technology developmentHalleck Creek plans dense media and wet magnetic separation to about 3.5% TREO before any chemical step.OSTI: production from allanite poses economic challenges and needs significant technology development.	US supply today: None. Allanite is the host mineral at Halleck Creek (development) and La Paz (exploration); neither is in production.Halleck Creek DevelopmentBokan Mountain ExplorationSheep Creek ExplorationLa Paz Exploration	Capitan Mountains, Gold Hill and White Signal
YttrofluoriteYttrium-bearing calcium fluoride(Ca,Y)F₂Rare earth oxide: not given by the USGS	Yttrium and heavy rare earths. Round Top oxide is 5.7% dysprosium and 0.9% terbium (OSTI) and about 72% heavy rare earths plus yttrium (company-reported).	Not stated in the sources checked.	Needs technology developmentRound Top plans a leach and chromatography flowsheet that is still being proven; its Wheat Ridge demonstration plant made dysprosium and NdPr oxide samples in Jul 2026.OSTI: production from yttrofluorite poses economic challenges and needs significant technology development.	US supply today: None. Round Top, Texas, is in development.Round Top Development	None

Which projects name a mineral comes from each project's deposit description in this directory, plus the OSTI review's Table A3 for Elk Creek. A project that is not listed names none of the five. The USGS districts are those on the historic deposits page whose USGS record names the mineral. Formulas and oxide shares are the USGS's, from its 2010 report (Table 3).

Verified Oct 1, 2026 Every row links to a full profile where one exists.

Download the data: USGS 2002 sites by mineral (CSV)USGS 2002 sites by mineral (JSON)Minerals (CSV)Minerals (JSON)Projects by mineral (CSV)Projects by mineral (JSON)

Which rare earth minerals does the US produce today?

The US produces two rare earth minerals: bastnaesite, mined as a primary product at Mountain Pass, California, and monazite, produced from heavy-mineral-sand concentrates in the southeast. The USGS estimates 51,000 t of rare earth oxide in concentrate for 2025, almost all from Mountain Pass.

Allanite, xenotime and yttrofluorite are not produced as primary minerals. Yttrium-rich xenotime is a minor part of the Florida monazite concentrates (USGS), and yttrium is about 0.12% of the rare earths in Mountain Pass ore (USGS).

Mined Bastnaesite The mineral at Mountain Pass, the only US mine that produces rare earths as its main product. It sits in a carbonatite, and flotation makes a concentrate of about 60% TREO.
Recovered as a by-product Monazite Chemours recovers it while mining titanium and zirconium sands in Florida and Georgia, and Energy Fuels separates it at White Mesa Mill in Utah.
Not produced Allanite, xenotime and yttrofluorite Halleck Creek and La Paz (allanite) and Round Top (yttrofluorite and xenotime) are in development or exploration.

Which mineral does each US rare earth project depend on?

Mountain Pass, Bear Lodge, Elk Creek, Bokan Mountain and Sheep Creek name bastnaesite, and Halleck Creek, Bokan Mountain, Sheep Creek and La Paz name allanite. Round Top names yttrofluorite and xenotime, and White Mesa Mill processes monazite. 5 sites name none of the minerals: Brook Mine, Colosseum, Silicon Ridge and the thorium-vein districts Lemhi Pass and Diamond Creek.

Every tracked US project and the rare earth minerals its deposit description names
Project	Status	Minerals named	Deposit, as described here
Mountain PassCalifornia	Producing	Bastnaesite	Carbonatite; bastnaesite
White Mesa MillUtah	Plant operating	Monazite	Monazite separation and uranium mill
Bear LodgeWyoming	Development	Bastnaesite	Carbonatite; bastnaesite
Brook MineWyoming	Development	Names none of the five	Coal-hosted unconventional deposit
Elk CreekNebraska	Development	Bastnaesite, Monazite	Carbonatite; niobium-scandium-titanium with magnet rare earthsMinerals from the OSTI review, Table A3.
Halleck CreekWyoming	Development	Allanite	A-type granite; allanite
Round TopTexas	Development	Xenotime, Yttrofluorite	Peralkaline rhyolite; yttrofluorite and xenotime; heavy-rare-earth rich
Bokan MountainAlaska	Exploration	Bastnaesite, Monazite, Xenotime, Allanite	Peralkaline complex; allanite, bastnaesite, monazite, xenotime; heavy-rare-earth rich
ColosseumCalifornia	Exploration	Names none of the five	Gold-first project with rare earth potential
Diamond CreekIdaho	Exploration	Thorium-bearing veins; no rare earth mineral is named	Thorium-rare earth belt; yttrium-rich
La PazArizona	Exploration	Allanite	Allanite-bearing; low grade
Lemhi PassIdaho, Montana	Exploration	Thorium-bearing veins; no rare earth mineral is named	Thorium-rare earth vein district
Sheep CreekMontana	Exploration	Bastnaesite, Monazite, Allanite	Carbonatite; bastnaesite, allanite, monazite
Silicon RidgeUtah	Exploration	Names none of the five	Halloysite-hosted ion-adsorption clay

The deposit text is the one shown on each project page. A mill is listed for the mineral it processes. Brook Mine recovers rare earths from coal, Colosseum is a gold-first project and Silicon Ridge is a clay system, so none of them is tied to one of these minerals.

Which rare earth mineral is easiest to process?

Bastnaesite and monazite are the easiest to process because both have been demonstrated at commercial scale, xenotime to some extent, while allanite and yttrofluorite need significant technology development (OSTI). The USGS adds that deposits whose rare earths sit mainly in one mineral have a competitive advantage.

Mountain Pass is the clearest case: one mineral, one flotation circuit, then separation. Round Top and Bokan Mountain hold several minerals that need different methods, which is why the stage of a project says more about risk than its grade.

Proven at commercial scale Bastnaesite Froth flotation makes a concentrate of about 60% TREO. Mountain Pass roasts it at about 600 °C and leaches it in cold hydrochloric acid.
Proven at commercial scale Monazite A heavy mineral, concentrated from sand by gravity, magnetic and electrostatic separation to 50% to 60% or more TREO. White Mesa Mill cracks it with caustic soda and leaches it with hydrochloric acid.
Demonstrated to some extent Xenotime Usually recovered with other minerals. In Florida, yttrium-rich xenotime is in the monazite concentrates from the sand operations (USGS).
Needs technology development Allanite Halleck Creek plans dense media and wet magnetic separation to about 3.5% TREO before any chemical step.
Needs technology development Yttrofluorite Round Top plans a leach and chromatography flowsheet that is still being proven; its Wheat Ridge demonstration plant made dysprosium and NdPr oxide samples in Jul 2026.

Which rare earth mineral carries the heavy rare earths?

Xenotime and yttrofluorite carry the heavy rare earths, and bastnaesite carries almost none. Mountain Pass oxide is 0.0% dysprosium and terbium, Round Top is 5.7% and 0.9%, and monazite sand concentrates are typically 1% to 3% dysprosium oxide (OSTI).

The USGS says deposits enriched in heavy rare earths most commonly have xenotime as the principal rare earth mineral. China licenses dysprosium and terbium exports, so the mineral that holds them matters for supply; see China's export controls.

What the oxide looks like by mineral source: share of total rare earth oxide
Source	Mineral	Lanthanum and cerium	NdPr	Dysprosium	Terbium
Mountain Pass	Bastnaesite	82.7%	16.4%	0.0%	0.0%
Round Top	Yttrofluorite and xenotime	32.4%	11.8%	5.7%	0.9%
Monazite concentrate from sands, typical	Monazite	Not stated	20% to 24%	1% to 3%	0.3% to 1%
White Mesa Mill blended monazite feed	Monazite	Not stated	22.4%	1.1%	0.3%

Figures are from the OSTI review (Table A2 and text); the columns do not sum to 100% because other rare earths are omitted. The mineral column is the mineral the directory names for the project. Round Top is about 72% heavy rare earths plus yttrium (company-reported).

Which rare earth minerals contain thorium?

Monazite is the thorium mineral: the USGS lists up to 20% thorium oxide in it, against 0 to 0.3% in bastnaesite and 0 to 3% in allanite, and tighter rules on radioactive minerals drove many monazite sources out of the market in the 1980s. Thorite veins carry thorium as the main metal.

Processing thorium-bearing material can need a radioactive materials license on top of the usual mining permits; the NRC and Agreement State licensing page explains how it works. White Mesa Mill processes monazite under Utah Radioactive Materials License UT1900479.

Thorium-heavy Monazite Yes. The USGS lists up to 20% thorium oxide and up to 16% uranium oxide, and says tighter rules on radioactive minerals drove many monazite sources out of the market in the 1980s.
Thorium present Allanite Some. The USGS lists 0 to 3% thorium oxide and says allanite grains are commonly damaged by its radioactive decay. La Paz is reported to be low in thorium and uranium (company-reported).
Thorium in the veins Thorite veins Lemhi Pass (Idaho and Montana) and Diamond Creek (Idaho) are thorium-rare earth vein districts, and the Lemhi Pass veins are thorite-bearing. Thorite is a thorium silicate, so thorium is its main metal.

Where else in the US do these minerals occur?

The USGS describes 13 districts beyond the tracked projects that carry these minerals, among them monazite placers in Idaho, the Carolinas, Florida and Georgia, thorium veins in Colorado and New Mexico, and the Pea Ridge iron mine in Missouri. None has a modern resource estimate. The cards link each to its USGS record.

A USGS figure is a decades-old estimate made under no modern reporting code and is never a reserve; see historic and prospect deposits.

2 districts Bastnaesite Wet Mountains (Colorado), Gallinas Mountains (New Mexico)
8 districts Monazite Wet Mountains (Colorado), Idaho monazite placers (Idaho), Hicks Dome (Illinois), Pea Ridge (Missouri), El Porvenir (New Mexico), Petaca district (New Mexico), Carolina monazite placers (North Carolina, South Carolina), Florida and Georgia beach placers (Florida, Georgia)
3 districts Xenotime Music Valley (California), Pea Ridge (Missouri), Laughlin Peak (New Mexico)
2 districts Allanite Capitan Mountains (New Mexico), Gold Hill and White Signal (New Mexico)

Go deeper

How else can I browse US rare earth mines?

Each page has its own definition and comparison table. The profiles behind them carry the sources.

Types of US rare earth depositsCarbonatite, granite, clay and sand deposits and their minerals
How rare earths are minedFlotation, gravity separation and leaching by mineral
How rare earths are separatedWhat happens after the mineral is cracked
NRC and Agreement State licensingThe radioactive materials rules behind thorium-bearing minerals
Mountain PassThe bastnaesite mine
White Mesa MillThe monazite mill
Historic and prospect depositsThe USGS-described districts that carry these minerals
US producers by elementWho makes each rare earth element

Questions about rare earth minerals in the US

What is the main rare earth mineral in the US?

Bastnaesite. It is mined as a primary product at Mountain Pass in California, the only US mine that produces rare earths as its main product, and the USGS estimates 51,000 t of rare earth oxide in concentrate for 2025.

Is monazite radioactive?

Yes. The USGS lists up to 20% thorium oxide and up to 16% uranium oxide in monazite, and says tighter rules on radioactive minerals drove many monazite sources out of the market in the 1980s. White Mesa Mill in Utah processes it under a state radioactive materials license.

What is the difference between bastnaesite and monazite?

Bastnaesite is a rare earth fluorocarbonate, (Ce,La,Y)CO3F, floated from carbonatite at Mountain Pass and mostly light rare earths. Monazite is a rare earth and thorium phosphate, (Ce,La,Y,Th)PO4, recovered from sands and carrying some dysprosium and terbium.

Which rare earth mineral has the most heavy rare earths?

Xenotime, according to the USGS, which says deposits enriched in heavy rare earths most commonly have it as the principal mineral. Round Top, named for yttrofluorite and xenotime, is 5.7% dysprosium and 0.9% terbium by oxide (OSTI).

What is allanite?

A rare earth silicate of the epidote group that carries cerium, lanthanum and yttrium. The USGS calls it common in igneous rocks but rarely concentrated enough to be an ore. Halleck Creek in Wyoming and La Paz in Arizona are allanite projects.

What mineral is at Round Top?

Round Top, Texas is named for yttrofluorite and xenotime in a peralkaline rhyolite, with about 72% of its oxide heavy rare earths plus yttrium (company-reported). OSTI says production from yttrofluorite needs significant technology development.

Does the US mine monazite?

Not as a primary product. Monazite is a by-product of titanium and zirconium sand mining in Florida and Georgia; the USGS says it is produced from heavy-mineral-sand concentrates in the southeast, and Chemours supplies about 500 t/yr to Energy Fuels (company-reported).

Sources and verification

Each profile lists its sources, a confidence grade and a verification date. Order of authority: official records (SEC filings, agency documents), company documents and technical reports, research papers, then independent press. Syndicated copies and reference works are labeled and are never the only source for a number. Company-reported figures are labeled as such, and non-binding deals are labeled "letter of intent" or "conditional".

USGS: The Principal Rare Earth Elements Deposits of the United States (Scientific Investigations Report 2010-5220) Official record
USGS Mineral Commodity Summaries 2026 Official record
OSTI review, Minerals Engineering 249 (Kashyap et al., 2026) Research paper
USGS Mineral Commodity Summaries 2026: Yttrium Official record
Utah DEQ: Radioactive Materials License UT1900479, White Mesa Mill Official record
Energy Fuels 10-K for 2025 (SEC) Official record

Tags show what kind of source each link is. How sources are ranked