Rare earth glossary: TREO, HREE, NdPr, SX, PFS and more

Current report to the SEC

The report a US-listed company files with the SEC when something material happens between its regular reports, such as a major agreement or an acquisition. Agreements and their exhibits are often filed with it.

The Jul 2025 agreements between MP Materials and the Department of Defense were filed with an 8-K.

See also10-K10-QSEC

Read moreThe MP Materials Pentagon deal

Annual report to the SEC

The annual report that a US-listed company files with the SEC. It gives audited accounts, a description of the business and its risks, and for a mining company, its resource and reserve disclosure.

See also10-Q8-KSECTechnical report summary

Quarterly report to the SEC

The quarterly report a US-listed company files with the SEC for each of the first three quarters, with unaudited accounts and an update on the business. It is where a plan or a schedule is often restated or moved.

See also10-K8-KSEC

A state that has signed an agreement with the NRC under which the state, not the NRC, licenses and inspects source material and certain other radioactive material. 40 states are Agreement States.

Of the 25 states with a page in this directory, 5 are not: Alaska, Montana, Idaho, Indiana and Missouri. In those states the NRC would license a project's source material.

See alsoNRCSource material

Read moreWho licenses it: the NRC or the stateRare earth by US state

SourceNRC: Agreement States

A rare earth silicate (epidote group) with 3% to 51% rare earth oxide. The host mineral at Halleck Creek and La Paz: huge tonnage, low grade.

Not produced in the US. Allanite is the host mineral at Halleck Creek (development) and La Paz (exploration); neither is in production.

See alsoGrade

Read moreAllanite and the US projects that name it

A grade quoted on the ash left after burning coal, not on the coal itself. A rare earth grade on an ash basis is higher than the grade of the coal it came from.

Brook Mine in Wyoming reports 450 to 570 ppm on an ash basis (company-reported).

See alsoGradeUnconventional source

Read moreBrook Mine

The mix of rare earths in a deposit, by each element's share of the oxide. Two deposits with the same TREO grade can be worth very different amounts if one is mostly cerium and lanthanum and the other holds more NdPr, dysprosium and terbium.

In MP Materials' reserve model, NdPr oxide is priced at $134.49/kg and lanthanum carbonate at $1.46/kg, and NdPr is only about 16% of the concentrate.

See alsoTREONdPrCerium and lanthanumHeavy rare earths

Read moreIs a higher TREO grade always better?

A rare earth fluorocarbonate ((Ce,La,Y)CO₃F) with 70% to 74% rare earth oxide. The mineral at Mountain Pass, the only US mine that produces rare earths as its main product.

Mined as a primary product at Mountain Pass, California (USGS 2026).

See alsoCarbonatiteFlotation

Read moreBastnaesite and the US projects that name it

The waste left after alumina is extracted from bauxite, often called red mud. It can hold scandium and rare earths, and it exists in large stockpiles.

A Department of Energy selection in Jun 2026 would fund a plant by the Colorado School of Mines and ElementUSA to recover rare earths from bauxite residue at Gramercy, Louisiana. A selection is not an award.

See alsoUnconventional sourceSelected for award negotiationYttrium and scandium

Read moreRare earth in Louisiana

NdFeB magnets made by holding magnet powder in a resin. They are weaker than sintered magnets but can be molded into complex shapes.

See alsoSintered NdFeBNdFeB magnet

Read moreSintered, bonded and samarium cobalt magnets

A roughly cylindrical body of broken rock fragments cemented together, formed where fluids or gas forced their way upward. Some host rare earths.

The USGS describes four rare earth breccia pipes cutting the iron orebody at Pea Ridge in Missouri.

See alsoHistoric or prospect depositMonaziteXenotime

Read moreRare earth in Missouri

A material recovered as a secondary output of mining or processing something else. The by-product's value helps pay for the main operation, but its supply depends on the main product's market.

Monazite is a by-product of heavy mineral sands mining, and at Elk Creek in Nebraska rare earths are a by-product stream of a niobium, scandium and titanium project.

See alsoHeavy mineral sandsMonaziteUnconventional source

Read moreElk Creek

Under NRC rules, tailings or wastes from ore processed primarily for its uranium or thorium content. Wastes from ore processed primarily for rare earths do not fit that definition, which is one reason the licensing of rare earth waste is a separate question.

See alsoSource materialTailingsNRC

Read moreWhen radioactive materials licensing applies

SourceeCFR: 10 CFR 40.4, definitions (source material and byproduct material)

Capital expenditure and operating expenditure

Capital expenditure (capex) is the up-front cost to build a mine or plant; operating expenditure (opex) is what it costs to run each year. A study states both, and capex usually rises between the scoping study and the feasibility study.

See alsoNPVDFSFID

Read moreHow long and how costly it is to open a mine

An igneous rock made mostly of carbonate minerals rather than silicates. Carbonatites hold about 54% of the world's known rare earth resources (OSTI), mostly as bastnaesite, and the rare earths in them are mainly light ones.

The tracked carbonatite deposits are Mountain Pass, Bear Lodge, Elk Creek and Sheep Creek.

See alsoBastnaesiteLight rare earthsPeralkaline rock

Read moreWhat distinguishes each type of depositMountain Pass

Two light rare earths that are most of the oxide in some ores: together 82.7% at Mountain Pass (OSTI). They sell for little, $1.71/kg for cerium oxide and $1.00/kg for lanthanum oxide in 2025 (USGS, Argus).

Main uses: catalysts, the leading domestic use of rare earths (USGS), and glass and polishing.

See alsoLight rare earthsMischmetalBasket

Read moreUS producers of cerium and lanthanum

Licensing rules from China's Ministry of Commerce: an exporter must apply for a license for each listed item, and the ministry decides each application case by case. 7 elements have needed a license since Apr 4, 2025: scandium, yttrium, samarium, gadolinium, terbium, dysprosium and lutetium. A wider set of measures announced on Oct 9, 2025, adding 5 more elements, is suspended until Nov 10, 2026.

A license is not a ban. Neodymium and praseodymium are on neither list.

See alsoMOFCOMDual-useHeavy rare earths

Read moreWhat China’s controls areWhich elements China controlsWhat happens on Nov 10, 2026

SourceMOFCOM: Announcement No. 18 of 2025 on medium and heavy rare earth itemsHolland & Knight: China imposes export controls on medium and heavy rare earth materials (Apr 2025)

CHIPS and Science Act funding

Funding and equity from the Department of Commerce under the CHIPS and Science Act. Commerce's CHIPS Program Office issued a preliminary letter of intent to Vulcan Elements in Nov 2025.

See alsoLetter of intent and MoUGovernment equity stake

Read moreWhich companies the government has taken equity in

SourceCommerce CHIPS Program Office: preliminary letter of intent for Vulcan Elements (Nov 3, 2025)

Commissioning is the testing of a new plant before it runs commercially; ramp-up is the period after start-up while output climbs toward nameplate capacity. A plant can be commissioning for months and ramp up for years.

See alsoNameplate capacityProducingFID

Read moreWhat is changing now

A figure, date or status that comes from the company itself and has not been confirmed by a filing, an agency or an independent source. Pages label these figures "company-reported" next to the number.

Resource sizes, capacity and schedules are the usual cases: a company's claim about its own deposit or plant is a statement, and it is shown as one.

See alsoStated capacityPrimary sourceConfidence grade

Read moreMethodology: how a fact is verified

Ore upgraded by crushing, grinding and physical or chemical methods until it is rich enough to ship or process further. A bastnaesite concentrate from flotation is about 60% TREO.

Mining and concentrating is the first of the five steps from ore to magnet. A concentrate is not a separated product: it still holds all the rare earths together.

See alsoFlotationMixed rare earth carbonateSeparationREO

Read moreWhat happens between the mine and a concentrate

A commitment, usually to lend, that depends on conditions being met, such as completing documents, raising other money or passing a credit review. It is firmer than a letter of interest and short of a closed loan.

The Office of Strategic Capital's joint conditional loan commitment to Vulcan Elements and ReElement in Nov 2025 is $700M.

See alsoOffice of Strategic CapitalLetter of interestSupport status labels

Read moreGovernment support tracker

SourceDepartment of War: Office of Strategic Capital joint $700M conditional loan commitment with Vulcan Elements and ReElement (Nov 2025)

The grade a record carries for how well its facts are confirmed. High: owner, status, location and the headline figures are confirmed in primary sources, and the sources agree. Medium-High: the main facts are confirmed in at least one primary source. Some figures rest on the company, and say so. Medium: identity facts are confirmed, but key figures rest on press, historic data or a company claim, or the sources conflict and the page shows both. Low: one source, or a company claim that nothing else supports. Treat as a lead, not a fact.

A grade is set by the evidence a record cites, and the build fails if a record is graded above what its sources support.

See alsoPrimary sourceCompany-reported

Read moreMethodology: what the grades mean

Tonnage times grade: the oxide held in the mineralized material, before any loss in mining and processing. It is a measure of what is in the ground, not of what a mine would recover.

Halleck Creek's 2,630 Mt at 3,292 ppm TREO holds about 8.66 Mt of contained oxide.

See alsoTREOGradeRecoveryMineral resource

Read moreHow to calculate contained TREO

The two FAST-41 listings. A covered project is accepted into the program and entitled to a comprehensive permitting timetable managed on the dashboard. A transparency project is posted on the dashboard at the Executive Director's direction, with a scheduled timeline, without full coverage.

Bear Lodge is covered, and Sheep Creek is a transparency project.

See alsoFAST-41

Read moreCovered and transparency projectsWhich US rare earth projects are in FAST-41

Breaking down a rare earth mineral's crystal structure, usually with heat and acid or caustic, so the rare earths can dissolve. It is the first chemical step in processing a concentrate of bastnaesite or monazite.

See alsoLeachingConcentrateMonaziteBastnaesite

Read moreHow rare earths are separated

Minerals that a government lists as essential to its economy or security and exposed to supply disruption. In the US the USGS publishes the list, and the rare earths are on it.

Many support programs are written around the list, including the Department of Energy's rare earth funding and Project Vault.

See alsoProject VaultDOE

Read moreRare earth policy

The grade that separates material of economic value from waste. A lower cut-off brings in more tonnes at a lower average grade, so an estimate must state the cut-off it used.

Mountain Pass reports reserves at a 2.50% TREO cut-off and resources at 2.15%.

See alsoGradeMineral resourceMineral reserve

Read moreTerms in a resource estimate

Defense Production Act

The part of the Defense Production Act that lets the government support domestic production of materials critical to national defense, with tools such as grants, loans and purchase commitments.

MP Materials' 10-K says the Department of War relies on Title III and other authorities for its deal with MP, and calls that use unconventional. The Department of War made a $5.1M Title III award to REEcycle in Jan 2025.

See alsoPrice floorDepartment of War

Read moreConditions and risks in the Pentagon deal

SourceMP Materials 10-K for 2025 (SEC)

The name the current administration uses for the Department of Defense (DoD). This directory writes Department of War for recent actions and keeps the Department of Defense where a 2025 agreement or filing uses that name, usually as "the Department of Defense, now the Department of War".

See alsoOffice of Strategic CapitalPrice floorDFARS

Read moreThe MP Materials Pentagon deal

A number this directory calculated from sourced figures rather than copying it from a source, such as contained oxide from tonnage and grade. Derived numbers say how they were derived.

See alsoContained TREOCompany-reported

Read moreMethodology: how numbers are written

The stage after a resource is defined, when feasibility studies, permits and financing are worked on before construction begins. No commercial rare earth output has started.

This directory's Development label means "resource defined; feasibility, permitting or financing under way; no commercial rare earth output." 5 of the 14 tracked mines and projects carry it.

See alsoExplorationProducingPFSDFSFID

Read moreRare earth projects in developmentWhich US projects are at which stage

Defense Federal Acquisition Regulation Supplement

The rules the Department of War adds to the federal acquisition rules for its contracts. Clause 252.225-7052 bars contractors from delivering samarium-cobalt and NdFeB magnets, and certain tantalum and tungsten products, made in or from material mined, refined or separated in China, Russia, Iran or North Korea. From Jan 1, 2027 the bar reaches back to the mine.

See alsoSmCo magnetNdFeB magnetNonavailability determinationExecutive Order 14415

Read moreWhat DFARS 252.225-7052 isWhat changes on Jan 1, 2027

SourceAcquisition.gov: DFARS 252.225-7052 (May 2024)

US International Development Finance Corporation

The US International Development Finance Corporation, which makes loans and takes equity warrants in projects outside the United States.

Its warrants in Serra Verde, a Brazilian ionic clay mine, are for up to 12% of the company.

See alsoGovernment equity stakeWarrantIon-adsorption clay

Read moreWhich companies the government has taken equity in

Definitive feasibility study

A feasibility study, also called a definitive or bankable feasibility study. It adds detailed designs and costs to support a decision to finance and build, and it is the study lenders ask for.

Elk Creek in Nebraska has a 2026 feasibility study and awaits financing, and Round Top in Texas expects its definitive feasibility study in Q4 2026 (company-reported).

See alsoPFSFIDMineral reserveCapex and opex

Read moreScoping study, PFS and DFS comparedWhat to check when a company announces a milestone

SourceSEC: Modernization of Property Disclosures for Mining Registrants (Release 33-10570, Dec 2018)

Department of Energy

The US Department of Energy. Its Office of Critical Minerals and Energy Innovation runs the 2026 rare earth funding programs, and its 2022 assessment of the rare earth magnet supply chain is a main source for the guides here.

See alsoSelected for award negotiationOSTI review

Read moreDOE rare earth funding

SourceDepartment of Energy: Rare Earth Permanent Magnets, Supply Chain Deep Dive Assessment (Feb 2022)

Goods, materials or technology with both civilian and military uses. Export controls on dual-use items, such as China's rare earth measures, require a license for listed items, and a license is a decision by the exporting government, not a ban.

See alsoChina’s rare earth export controlsMOFCOM

Read moreWhat China’s controls are

The two heavy rare earths that let an NdFeB magnet keep its strength at high temperature, so high-temperature motors, such as electric vehicle traction motors, need them. Oxide averaged $239/kg for dysprosium and $1,010/kg for terbium in 2025 (USGS, Argus), against $69/kg for NdPr.

The USGS says no company produced heavy rare earths in sustained commercial quantities in 2025; Mountain Pass and White Mesa Mill are building circuits for them.

See alsoHeavy rare earthsGrain boundary diffusionNdFeB magnetSmCo magnet

Read moreUS producers of dysprosium and terbiumHow much a magnet needs

SourceUSGS Mineral Commodity Summaries 2026USGS Mineral Commodity Summaries 2026: Rare Earths (Heavy)

Earth Mapping Resources Initiative

The USGS's Earth Mapping Resources Initiative, which works with state geological surveys to map geology and collect airborne geophysical data across the US, to find where critical minerals may be.

It funds the Illinois State Geological Survey's work on Hicks Dome.

See alsoUSGSOccurrenceCritical minerals

Read moreRare earth in Illinois

Magnets in products that have reached the end of their use: electric vehicle motors, wind turbines, hard drives. They are the next large source of recycled rare earths, after swarf, but they are scattered and costly to collect and take apart.

See alsoSwarfHydrogen processing of magnet scrap

Read moreWhy rare earth recycling is still small

The Jul 20, 2026 executive order on defense supply chains. It does not move the Jan 1, 2027 date of the DFARS rule. It limits nonavailability waivers from that day and adds supply chain mapping and alternative-source requirements with deadlines running to Apr 2027.

See alsoDFARSNonavailability determination

Read moreWhat Executive Order 14415 changes

SourceThe White House: Executive Order 14415 on defense supply chains (Jul 20, 2026)

Export-Import Bank of the United States

The Export-Import Bank of the United States, a federal agency that makes loans and issues letters of interest to support US exports. EXIM approved the Project Vault loan of up to $10 billion in Feb 2026.

See alsoLetter of interestProject Vault

Read moreGovernment support tracker

The first stage of a mining project: drilling, sampling and mapping to find and outline mineralization, before there is a resource estimate good enough for a feasibility study.

This directory's Exploration label means "drilling or sampling; no feasibility-grade resource, or no rare earth resource estimate yet." 7 of the 14 tracked mines and projects carry it.

See alsoDevelopmentScoping studyMineral resource

Read moreThe stages of a rare earth projectHow the stages map to the status labels

Title 41 of the Fixing America’s Surface Transportation Act

A federal permitting program that sets a published timetable for every agency permit a qualifying project needs and tracks it on a public dashboard. It is a process, not money: it sets dates and coordinates agencies, and it does not decide whether a permit is granted.

Two rare earth projects tracked here are in it: Bear Lodge in Wyoming as a covered project and Sheep Creek in Montana as a transparency project.

See alsoCovered project and transparency projectNRC

Read moreWhat FAST-41 isWhat FAST-41 does not do

SourcePermitting Council: Bear Lodge Rare Earth project gains FAST-41 coverage (Mar 20, 2026)

Final investment decision

The point at which a project's owners commit to build it, after the study, permits, financing and sales agreements are in place. Until then a schedule is a target.

Energy Fuels says Phase 2 at White Mesa Mill, which is not under construction, is expected by mid-2029, subject to licensing, financing, feed and a final investment decision (company-reported).

See alsoDFSCapex and opexCommissioning and ramp-up

Read moreEnergy Fuels

A method that lifts wanted minerals out of ground ore: the ore is mixed with water and reagents, and air bubbles carry the wanted particles to the surface as a froth. Bastnaesite floats; monazite is heavy and magnetic and is concentrated by other means.

See alsoConcentrateBastnaesiteMonaziteRecovery

Read moreWhy the deposit type decides the mining method

Free on board

A price term: the seller's price includes loading the goods on the ship at the port of origin, and the buyer pays the sea freight and insurance. The USGS rare earth prices used here are Argus Media averages quoted free on board.

See alsoNdPrUSGS

Read moreNdPr prices and producers

SourceUSGS Mineral Commodity Summaries 2026

A government right to a share of a company, held as common shares, as preferred stock that can convert into shares, or as warrants that allow buying shares at a set price. A stake of "up to 19.9%" or "15% fully converted and exercised" describes shares the government could hold, not shares it holds today.

Among the rare earth companies tracked here, MP Materials is the only equity stake confirmed as issued.

See alsoWarrantPrice floorCHIPS funding

Read moreHow government equity stakes workWhich stakes are confirmed

Concentration of the target material in rock

The concentration of the target material in rock. For rare earths it is TREO as a percentage or in parts per million (ppm); one percent is 10,000 ppm. A lower grade means more rock to dig, crush and leach for each tonne of oxide.

About 17 t of mineralized material holds a tonne of oxide at Mountain Pass (5.98%), against about 304 t at Halleck Creek (0.33%).

See alsoTREOCut-off gradeContained TREO

Read moreHow much rock it takes to get a tonne of oxide

A way of adding dysprosium or terbium only at the surfaces of the magnet's grains, where it works best, so a magnet gets its heat resistance with much less heavy rare earth. Magnet makers use it to reduce the amount they need.

See alsoDysprosium and terbiumSintered NdFeBHeavy rare earths

Read moreHow much dysprosium and terbium a magnet needs

Crushed ore is stacked in a heap and a leaching solution is trickled through it; the dissolved metals drain out at the bottom and are collected. It needs no fine grinding or large plant, so it suits low-grade ore.

The mining guide lists heap leaching for some granite and rhyolite deposits.

See alsoLeachingPeralkaline rockIon-adsorption clay

Read moreHow rare earths are mined

Sand deposits, usually along old shorelines, that hold heavy minerals such as ilmenite and zircon, and often monazite. The sand is mined for titanium and zirconium minerals, and monazite is a by-product.

In the US, Chemours mines heavy mineral sands in Florida, and monazite from its Offerman plant in Georgia has supplied Energy Fuels' White Mesa Mill in Utah.

See alsoMonaziteBy-productPlacer

Read moreRare earth in FloridaRare earth in Georgia

Heavy rare earth elements (or oxides)

The heavier rare earths, usually gadolinium or dysprosium through lutetium, plus yttrium. In most ore they are a small share of the oxide, and they sell for far more than the light ones. Dysprosium and terbium matter most, because they let a magnet keep its strength when hot.

China has required export licenses for 7 elements, among them dysprosium and terbium, since Apr 2025, and deposits rich in heavy rare earths, such as the peralkaline and clay types, draw attention for that reason.

See alsoDysprosium and terbiumLight rare earthsPeralkaline rockChina’s rare earth export controls

Read moreWhich deposit types hold the most heavy rare earths

A known rare earth occurrence in USGS data with no current development program. This directory does not track these as projects: it lists 22 principal districts, set beside any company activity found since 2024.

A USGS resource figure for such a deposit is an old estimate made under no modern reporting code, never a reserve.

See alsoOccurrenceMineral resourceThorium and rare earth veins

Read moreHistoric and prospect deposits

Exposing alloy flakes to hydrogen, which the alloy absorbs and which makes it crumble into a coarse powder, ready for jet milling. The same effect is the basis of hydrogen processing of magnet scrap.

See alsoStrip castingJet millingHydrogen processing of magnet scrap

Read moreHow rare earth magnets are made

A recycling method in which scrap magnets are exposed to hydrogen, which breaks them into a powder that can be made into new magnets. It recovers the alloy without separating it into oxides again.

HyProMag USA plans a Texas plant for mid-2027.

See alsoHydrogen decrepitationSwarfEnd-of-life magnets

Read moreHow rare earth recycling is done

The part of a mineral resource estimated from adequate geological evidence and sampling: enough to support a mine plan and an economic assessment, but with less certainty than a measured resource.

La Paz in Arizona reports 35.2 Mt indicated and 135.4 Mt inferred.

See alsoMeasured resourceInferred resourceProven and probable reserves

Read moreWhat measured, indicated and inferred mean

SourceeCFR: 17 CFR 229.1300, the S-K 1300 definitions for mining registrants

The part of a mineral resource estimated from limited geological evidence and sampling: the lowest confidence category. An inferred resource may not be used to assess economic viability, and it cannot become a reserve.

A scoping study may rely partly on inferred resources, which is why headline economics at that stage deserve caution.

See alsoMeasured resourceIndicated resourceScoping study

Read moreWhat measured, indicated and inferred mean

SourceeCFR: 17 CFR 229.1300, the S-K 1300 definitions for mining registrants

A clay formed by deep weathering of granite, in which rare earth ions cling to the clay and can be leached out with a salt solution instead of being crushed and milled out of rock. These clays are richer in heavy rare earths than carbonatite ore is.

Serra Verde in Brazil is an ionic clay mine that produces mixed rare earth carbonate, and USA Rare Earth has an offtake from it (company-reported).

See alsoHeavy rare earthsMixed rare earth carbonateOfftake agreement

Read moreWhy the deposit type decides the mining method

A separation method in which the solution passes through columns of resin that hold different rare earths in different places, so they come out one after another. It is an alternative to solvent extraction.

ReElement and USA Rare Earth use chromatography.

See alsoSeparationSolvent extractionRapidSX

Read moreRapidSX and ion-exchange chromatography compared

Internal rate of return

Internal rate of return: the discount rate at which a project's net present value is zero. A higher IRR means capital comes back faster, and like NPV it rests on an assumed price.

See alsoNPVCapex and opex

Grinding the coarse magnet powder to a fine powder by blowing it at high speed against itself in a stream of gas. The fine powder is what is pressed in a magnetic field.

See alsoHydrogen decrepitationSintering

Read moreHow rare earth magnets are made

Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves

The Australasian code for reporting mineral resources and ore reserves, in its 2012 edition. It is part of the listing rules of the Australian and New Zealand exchanges, so a company listed on the ASX reports its resources under it.

Like NI 43-101 and S-K 1300, it uses the measured, indicated and inferred categories and requires a competent person to sign the estimate.

See alsoNI 43-101S-K 1300Qualified personStock exchange listings

Read moreJORC, NI 43-101 and S-K 1300

SourceJORC Code, 2012 Edition (JORC Committee)

The 15 elements from lanthanum (atomic number 57) to lutetium (71). With scandium and yttrium they make up the rare earths.

Promethium, element 61, has no stable isotope and is not mined.

See alsoRare earth elements

Read moreThe 17 elements at a glance

Dissolving the wanted material out of ore or concentrate with an acid or another solution. It is the step that puts rare earths into solution so they can be separated. Mountain Pass leaches roasted bastnaesite in cold hydrochloric acid.

See alsoHeap leachingCrackingSeparation

Read moreHow rare earths are separated

Letter of intent; memorandum of understanding

A letter of intent (LOI) or memorandum of understanding (MoU) says two parties intend to make a deal. It is usually non-binding: the binding terms come in a later definitive agreement, and a deal can change or fall through before then.

Lynas USA's Mar 2026 agreement with the Department of War is a binding letter of intent; the Vulcan Elements Commerce item is a non-binding letter of intent.

See alsoOfftake agreementLetter of interestSupport status labels

Read moreWhich equity stakes are confirmed

A non-binding letter from a lender, such as EXIM, saying it may consider financing a project. It is not a loan approval and creates no obligation to lend.

HyProMag USA holds a non-binding EXIM letter of interest for up to $92M.

See alsoEXIMConditional commitmentLetter of intent and MoU

Read moreWhich US recycling projects have federal support

Light rare earth elements (or oxides)

The lighter rare earths, usually the first half of the series, from lanthanum to samarium or europium. They are most of the oxide in bastnaesite and monazite ores, and they include neodymium and praseodymium, the magnet metals.

Authors draw the line between light, medium and heavy in different places, so check how a report defines its groups before comparing two of them.

See alsoMedium rare earthsHeavy rare earthsNdPr

Read moreTerms in a resource estimate

The sintered block of magnet material, before it is cut, ground and coated into finished magnets. Magnet block is also stockpiled as an intermediate product.

The USGS lists NdFeB magnet block among the potential National Defense Stockpile acquisitions for fiscal 2025.

See alsoSinteringSintered NdFeBNational Defense Stockpile

Read moreProject Vault and the National Defense Stockpile

The part of a mineral resource estimated from conclusive geological evidence and sampling: the highest confidence category. Only measured and indicated resources can be converted to reserves.

See alsoIndicated resourceInferred resourceMineral resource

Read moreWhat measured, indicated and inferred mean

SourceeCFR: 17 CFR 229.1300, the S-K 1300 definitions for mining registrants

Medium rare earth elements (or oxides)

A middle group between the light and the heavy rare earths, used by some authors and by Chinese regulators, whose April 2025 rule is about "medium and heavy" rare earth items. There is no standard boundary.

Some reports, such as the OSTI review, split a deposit's oxide into light, medium and heavy shares; others use only two groups.

See alsoLight rare earthsHeavy rare earthsChina’s rare earth export controls

Read moreWhich elements China controls

SourceMOFCOM: Announcement No. 18 of 2025 on medium and heavy rare earth items

The step that turns separated oxides into rare earth metal and then alloy, usually by molten-salt electrolysis or reduction with calcium. It is the thinnest part of the US chain: the Department of Energy found no US metal refining in 2022.

See alsoMolten-salt electrolysisMetallothermic reductionRare earth alloyRare earth oxide (product)

Read moreWhat metallization is, and why it is the US bottleneckWhich US companies make metal or alloy

A way to make rare earth metal by reacting a rare earth fluoride with a more reactive metal, usually calcium, at high temperature. It is run in batches and makes dysprosium, terbium, yttrium and gadolinium.

See alsoMetallizationMolten-salt electrolysis

Read moreHow rare earth metal is made

The economically mineable part of a measured or indicated resource, shown by at least a pre-feasibility study, after allowing for losses in mining and processing. Reserves are called proven or probable.

Inferred resources cannot be converted to reserves, and a company may not call a resource a reserve until a study shows it can pay.

See alsoProven and probable reservesMineral resourcePFSDFS

Read moreWhat measured, indicated and inferred mean

SourceeCFR: 17 CFR 229.1300, the S-K 1300 definitions for mining registrants

A concentration of material in or on the earth's crust with reasonable prospects for economic extraction, sorted into inferred, indicated and measured by how well the evidence supports it. A resource is not a reserve and does not show that a mine would pay.

See alsoMineral reserveInferred resourceIndicated resourceMeasured resource

Read moreWhat measured, indicated and inferred mean

SourceeCFR: 17 CFR 229.1300, the S-K 1300 definitions for mining registrants

An unseparated alloy of light rare earth metals. The USGS price series is for a mix of 65% cerium and 35% lanthanum, which averaged $5.62/kg in 2025 (Argus).

See alsoCerium and lanthanumRare earth alloy

SourceUSGS Mineral Commodity Summaries 2026

An intermediate product: a precipitate of unseparated rare earths in carbonate form, sold to a separation plant. It is richer than a mine concentrate but is not yet split into single elements.

White Mesa Mill began selling a mixed rare earth carbonate from monazite in 2021, and Serra Verde in Brazil makes one from clay.

See alsoConcentrateSeparationIon-adsorption clayRare earth oxide (product)

Read moreUS producers by element

Ministry of Commerce of China

China's Ministry of Commerce, the agency that issues and administers China's export controls, including the rare earth announcements of Apr 4, 2025 and Oct 9, 2025.

See alsoChina’s rare earth export controls

Read moreWhat is controlled and what is suspended

A way to make rare earth metal: an electric current passes through the oxide dissolved in a bath of molten fluoride salt, and the metal collects at one electrode. It makes neodymium, praseodymium and dysprosium-iron alloy, and it uses far more energy than calcium reduction.

See alsoMetallizationMetallothermic reduction

Read moreHow rare earth metal is made

A rare earth and thorium phosphate ((Ce,La,Y,Th)PO₄) with 35% to 71% rare earth oxide. The by-product of titanium and zirconium sand mining that feeds White Mesa Mill.

Produced from heavy-mineral-sand concentrates in the southeastern US (USGS 2026) and processed at White Mesa Mill in Utah.

See alsoHeavy mineral sandsThorium and rare earth veinsCracking

Read moreMonazite and the US projects that name it

The most a plant is designed to make in a year, usually in tonnes per year. It is a design figure, not output, and a new plant takes time to reach it. A company may also give a target for a later phase.

This directory shows each owner's stated capacity as stated and never adds it to output.

See alsoStated capacityCommissioning and ramp-upTonne and short ton

Read moreCapacity tracker

The government's own stockpile of materials for defense needs, run by the Defense Logistics Agency. It is separate from Project Vault, which is a privately run reserve for commercial manufacturers.

The USGS lists potential fiscal 2025 acquisitions of 300 t of NdPr oxide, 450 t of NdFeB magnet block, 60 t of SmCo alloy and 1,100 t of lanthanum.

See alsoProject VaultMagnet block

Read moreProject Vault and the National Defense Stockpile

SourceUSGS Mineral Commodity Summaries 2026

Neodymium-iron-boron magnet

A permanent magnet made of neodymium, iron and boron, the strongest commercial type. It is used in electric vehicle motors, wind turbine generators, hard drives and defense systems, and it is the main use of NdPr.

Sintered NdFeB is about 93% of the NdFeB market (DOE, 2022).

See alsoSintered NdFeBBonded NdFeBSmCo magnetNdPr

Read moreSintered, bonded and samarium cobalt magnetsUS rare earth magnet manufacturers

SourceDepartment of Energy: Rare Earth Permanent Magnets, Supply Chain Deep Dive Assessment (Feb 2022)

Neodymium-praseodymium oxide

Neodymium (Nd) and praseodymium (Pr), the two light rare earths that give NdFeB magnets their strength, usually sold together as NdPr oxide or NdPr metal. NdPr oxide averaged $69/kg in 2025 (USGS, Argus).

NdPr is the product the Department of War's $110/kg price floor covers, and the main output of the two US separation sites, Mountain Pass and White Mesa Mill.

See alsoNdFeB magnetPrice floorSeparationLight rare earths

Read moreUS producers of NdPr oxide and metalHow rare earth magnets are made

SourceUSGS Mineral Commodity Summaries 2026

The USGS measure of how much of US use of a material is met by imports: imports minus exports, adjusted for changes in government and industry stocks, as a share of apparent consumption. For rare earth compounds and metals it was 67% in 2025 and 53% in 2024.

See alsoUSGS

Read moreThe five steps from mine to magnet

SourceUSGS Mineral Commodity Summaries 2026

National Instrument 43-101, Standards of Disclosure for Mineral Projects

The Canadian securities rule that sets how a company discloses scientific and technical information about a mineral project, including resource and reserve estimates. A qualified person must prepare or approve the technical report that supports the disclosure.

See alsoJORC CodeS-K 1300Qualified person

Read moreJORC, NI 43-101 and S-K 1300

SourceBritish Columbia Securities Commission: National Instrument 43-101, Standards of Disclosure for Mineral Projects (consolidation, Jul 25, 2023)

A Department of War finding that a covered material cannot be bought in satisfactory quality and sufficient quantity as and when needed, which can excuse a delivery from the DFARS bar.

Executive Order 14415 tells the Secretary of War to stop issuing nonavailability waivers from Jan 1, 2027 unless the contractor submits a formal mitigation plan.

See alsoDFARSExecutive Order 14415

Read moreWhat exceptions and waivers the rule has

Net present value

Net present value: the value today of a project's future cash flows after costs, discounted at a stated rate. Studies quote it at a stated discount rate and a stated price, so the same project has a different NPV at a different NdPr price.

See alsoIRRCapex and opexScoping study

Read moreWhat to check when a company announces a milestone

Nuclear Regulatory Commission

The Nuclear Regulatory Commission, the federal agency that regulates civilian use of radioactive materials. It licenses source material in the states that have not signed an agreement with it, and in the others the state does.

See alsoAgreement StateSource material

Read moreNRC and Agreement State licensing

A place where a mineral is found, with no finding yet that it is large or rich enough to mine. The Department of Energy reports rare earth occurrences in 19 states (OSTI).

See alsoHistoric or prospect depositMineral resourceExploration

Read moreHistoric and other US occurrences

A Department of War office that makes loans to companies building critical technology supply chains. It sits inside the Department of War and is counted with it in the support tracker.

See alsoConditional commitmentDepartment of War

Read moreGovernment support tracker

An agreement by a buyer to take some or all of a project's future output, often at a set or floor price. It shows lenders that the product has a buyer. A binding offtake commits the buyer, a non-binding one does not, and either depends on the plant being built.

The Department of War agreed in Jul 2025 to buy the output of MP Materials' 10X magnet plant for 10 years, and that offtake starts when the plant begins operating.

See alsoPrice floorLetter of intent and MoUFID

Read moreThe MP Materials Pentagon deal

Office of Scientific and Technical Information

The July 2026 peer-reviewed review of US rare earth deposits and production (Kashyap and others, Minerals Engineering 249), hosted by the Department of Energy's Office of Scientific and Technical Information. This directory uses it as a main source for resource figures and capacity.

See alsoUSGSDOEPrimary source

Read moreSources, by type

Igneous rock with more sodium and potassium than the aluminum in it can balance. Peralkaline granites and rhyolites can be richer in heavy rare earths than carbonatites are, which is why they matter for supply of dysprosium and terbium.

The directory groups alkaline granites, rhyolites and peralkaline complexes as one deposit type; Round Top in Texas and Bokan Mountain in Alaska, both rich in heavy rare earths, are in that group.

See alsoCarbonatiteHeavy rare earthsXenotime

Read moreWhich deposit types hold the most heavy rare earths

Pre-feasibility study

A pre-feasibility study: it picks a mining method and a processing route, estimates costs in more detail than a scoping study, and can support probable reserves. It is the step before a feasibility study.

Halleck Creek in Wyoming scheduled its pre-feasibility study for Q3 2026 (company-reported); this directory has not confirmed that it was released.

See alsoScoping studyDFSMineral reserve

Read moreScoping study, PFS and DFS comparedHalleck Creek

SourceSEC: Modernization of Property Disclosures for Mining Registrants (Release 33-10570, Dec 2018)

A pilot plant is a small plant that tests a process on real feed; a demonstration plant is larger and closer to commercial scale, built to prove the process before a commercial plant. Neither is commercial production.

The producer pages mark pilots apart from commercial operation, and the Department of Energy funds a demonstration facility program.

See alsoPlant operating, building and plannedSelected for award negotiationNameplate capacity

Read moreUS producers by elementDOE rare earth funding

A deposit of heavy minerals concentrated by flowing water in stream or beach sediment. Monazite placers in Idaho and the Carolinas were historic US sources of thorium and rare earths.

See alsoHeavy mineral sandsMonaziteHistoric or prospect deposit

Read moreHistoric and prospect deposits

The directory's three labels for processing and manufacturing plants. Operating: a plant that separates, refines, alloys, magnetizes or recycles, with commercial output under way. Building: a plant under construction or commissioning. Planned: a plant that is announced or financed but not yet under construction.

See alsoProducingNameplate capacityPilot and demonstration plants

Read moreMap of tracked sitesCapacity tracker

A contract under which the government pays a producer the difference when the market price falls below a set level. The NdPr price floor in MP Materials' deal with the Department of War is $110 per kilogram, runs from Oct 1, 2025 to Dec 31, 2035 and settles every quarter.

NdPr oxide averaged $69/kg in 2025, below the floor. MP Materials recognized $51.0M of price protection income in 2025.

See alsoNdPrOfftake agreementDepartment of War

Read moreWhat the NdPr price floor isHow the floor pays out each quarter

A source that can support a number, a date or a status on its own. This directory counts two kinds as primary: official records (SEC filings, and releases, reports or datasets from agencies and governments) and company documents (a company's own releases, reports and website). Press, syndicated copies and reference works corroborate but are never primary.

See alsoCompany-reportedConfidence grade

Read moreSources, by typeMethodology: which sources count

A mine or plant that is making a product for sale today, as opposed to one that is planned, being built or in testing.

This directory's Producing label means "mining or processing rare earth material for sale today." 1 of the 14 tracked mines and projects carries it: Mountain Pass.

See alsoDevelopmentNameplate capacityCommissioning and ramp-up

Read moreOperating rare earth mines and processing sites

The U.S. Strategic Critical Minerals Reserve: an independently run company, VaultCo, that buys and stores critical minerals in the United States for manufacturers, financed by an EXIM loan of up to $10 billion and private capital. EXIM's board approved the loan on Feb 2, 2026.

EXIM's announcements name no minerals, and the sources checked report no rare earth purchase yet.

See alsoEXIMNational Defense Stockpile

Read moreWhat Project Vault isDoes Project Vault buy rare earths

SourceEXIM: EXIM approves Project Vault loan (Feb 2, 2026)

The two reserve categories. A proven reserve is the economically mineable part of a measured resource; a probable reserve is the economically mineable part of an indicated resource, and in some cases of a measured one. Probable carries less confidence than proven.

See alsoMineral reserveMeasured resourceIndicated resource

Read moreWhat measured, indicated and inferred mean

SourceeCFR: 17 CFR 229.1300, the S-K 1300 definitions for mining registrants

The expert who signs a resource or reserve estimate, with at least five years of relevant experience and membership of a recognized professional body. S-K 1300 and NI 43-101 call this person qualified, and the JORC Code calls them competent.

See alsoJORC CodeNI 43-101S-K 1300

Read moreTerms in a resource estimate

Ucore's version of solvent extraction, which runs the same chemistry in a column instead of mixer-settler tanks, to cut the time and the footprint of a plant.

Ucore is building its Louisiana Strategic Metals Complex around it.

See alsoSolvent extractionIon-exchange chromatographySeparation

Read moreRapidSX and ion-exchange chromatography comparedUcore

Rare earth metal melted with iron and boron, and sometimes dysprosium, into the alloy that magnet makers use. A sintered NdFeB magnet is about 30% rare earth, 69% iron and 1% boron by weight. The alloy is cast, broken up and ground to a fine powder.

See alsoMetallizationStrip castingNdFeB magnetMischmetal

Read moreRare earth metal, alloy and magnet powder

The 17 metallic elements made up of the 15 lanthanides, from lanthanum to lutetium, plus scandium and yttrium. They occur together in the same ores and behave almost alike in chemistry, so splitting them apart takes many processing stages.

Despite the name, most are not scarce in the earth's crust. What is scarce is a deposit rich enough, and easy enough to process, to mine.

See alsoLanthanidesLight rare earthsHeavy rare earthsCritical minerals

Read moreThe 17 elements at a glanceWhy separating rare earths is so hard

The usual form of a separated rare earth: a powder of the element's oxide, such as NdPr oxide or dysprosium oxide. It is what separation plants sell, the form in which prices are quoted, and the feed for metal making.

See alsoSeparationMetallizationREONdPr

Read moreWhat rare earth metallization is

The share of the contained oxide that a process actually gets out. Recovery is always below 100%, and each ore needs its own flowsheet because no two rare earth ores are alike (USGS).

See alsoContained TREOFlotationConcentrate

Read moreWhat happens between the mine and a concentrate

Rare earth oxide

Rare earth oxide, used in most reports as another name for TREO. The USGS reports US mine output as rare earth oxide equivalent: an estimated 51,000 t in 2025.

See alsoTREORare earth oxide (product)Concentrate

Read moreHow tonnes of ore, oxide, metal and magnets compare

SourceUSGS Mineral Commodity Summaries 2026

Regulation S-K subpart 1300

The SEC's rule for mining companies that file in the US. It defines mineral resources and reserves in the same measured, indicated and inferred terms as JORC and NI 43-101, and it requires a technical report summary and a qualified person.

See alsoJORC CodeNI 43-101Technical report summarySEC

Read moreJORC, NI 43-101 and S-K 1300

SourceeCFR: 17 CFR 229.1300, the S-K 1300 definitions for mining registrantsSEC: Modernization of Property Disclosures for Mining Registrants (Release 33-10570, Dec 2018)

The rare earth used with cobalt to make samarium cobalt (SmCo) magnets, which resist heat better than NdFeB magnets and need no dysprosium or terbium. Samarium oxide averaged $2.82/kg in 2025 (USGS, Argus).

See alsoSmCo magnetDysprosium and terbium

Read moreUS producers of samarium

Preliminary economic assessment (PEA)

A first economic test of a project, called a preliminary economic assessment (PEA) under NI 43-101. It may rely partly on inferred resources and cannot support a reserve, so its numbers are early and can change a great deal at the next stage.

See alsoPFSDFSInferred resourceNI 43-101

Read moreScoping study, PFS and DFS compared

SourceCanadian Securities Administrators: Staff Notice 43-307 on preliminary economic assessments (2012)SEC: Modernization of Property Disclosures for Mining Registrants (Release 33-10570, Dec 2018)

Securities and Exchange Commission

The US Securities and Exchange Commission, which regulates companies listed in the US. Its filings (10-K, 10-Q, 8-K) are the primary source for most company facts here, and its S-K 1300 rule governs how mining companies report resources.

See also10-K8-KS-K 1300

Read moreMethodology

A Department of Energy step that picks a project to negotiate an award with, and commits no money. DOE states that selection is not a commitment to issue an award or provide funding, that it may cancel negotiations and rescind a selection for any reason, and that amounts are subject to change.

The 2026 DOE rare earth selections, two demonstration facilities and five coal-waste pilots, are at this stage.

See alsoDOEPilot and demonstration plantsSupport status labels

Read moreWhat "selected for award negotiations" means

The chemical process that splits a mixed rare earth solution into single-element products, usually oxides. It is hard because neighboring rare earths behave almost identically, so a circuit repeats the step many times. Two US sites separate rare earths commercially: Mountain Pass and White Mesa Mill.

The OSTI review counts 2 US sites with commercial separation, and the Department of Energy found that China did 89% of it in 2020.

See alsoSolvent extractionRapidSXIon-exchange chromatographyRare earth oxide (product)

Read moreWhy separating rare earths is so hardWhich US plants separate rare earths

SourceDepartment of Energy: Rare Earth Permanent Magnets, Supply Chain Deep Dive Assessment (Feb 2022)

The NdFeB magnets made by pressing alloy powder in a magnetic field and sintering it into a solid block. They are the strongest and the most used, and the type made in the five US plants listed as making sintered magnets.

See alsoNdFeB magnetBonded NdFeBSinteringMagnet block

Read moreWhich US plants make rare earth magnets

Heating pressed magnet powder, at 1,000 to 1,100 °C, until the particles fuse into a solid block without melting. The block is then machined, coated and magnetized. Machining causes the largest loss of material in making a magnet.

See alsoSintered NdFeBJet millingMagnet block

Read moreHow rare earth magnets are made

Samarium cobalt magnet

A permanent magnet made of samarium and cobalt. It resists heat better than NdFeB, uses no dysprosium or terbium, and is chosen where weight matters less than staying strong when hot.

Arnold Magnetic Technologies fabricates SmCo magnets in Rochester, New York. The DFARS rule covers both SmCo and NdFeB magnets.

See alsoSamariumNdFeB magnetDFARS

Read moreUS producers of samariumSintered, bonded and samarium cobalt magnets

The main way rare earths are separated. The rare earth solution is mixed with an organic liquid that carries an extractant, a chemical that binds one rare earth more strongly than its neighbor. The liquids settle apart, and the cycle repeats in a long series of mixer-settler stages.

A circuit needs from fewer than 100 to about 1,500 stages, which is why separation plants are large and costly. MP Materials and Energy Fuels use conventional solvent extraction.

See alsoSeparationRapidSXIon-exchange chromatography

Read moreHow solvent extraction works

Uranium or thorium in any form, or ore that holds 0.05% or more of either by weight. US law licenses the possession and processing of source material, and many rare earth ores carry enough thorium to be in scope once they are processed. Unrefined and unprocessed ore is exempt, and so are rare earth products with 0.25% or less thorium and uranium.

Monazite is the thorium-heavy rare earth mineral, and bastnaesite carries little.

See alsoNRCAgreement StateByproduct materialMonazite

Read moreWhy thorium and uranium make permitting harderWhen radioactive materials licensing applies

SourceeCFR: 10 CFR 40.4, definitions (source material and byproduct material)eCFR: 10 CFR 40.13, unimportant quantities of source material

An owner's own figure for what a plant can make or will make, in tonnes a year, shown as stated. It is a design figure or a target, never measured output, and this directory does not add it to output.

The capacity tracker adds stated capacity up unit by unit and says which units are operating, being built or planned.

See alsoNameplate capacityCompany-reportedPlant operating, building and planned

Read moreCapacity tracker

Where a company's shares trade. NYSE is the New York Stock Exchange and ASX the Australian Securities Exchange. TSX is the Toronto Stock Exchange, and TSXV its venture market for smaller companies. OTCQX and OTCQB are over-the-counter tiers, with lighter requirements than a national exchange.

A listing says where a company's shares trade, not how sound the company is. This directory gives no investment advice.

See alsoJORC CodeNI 43-101S-K 1300SEC

Read morePublicly traded rare earth companies in the US

Pouring molten magnet alloy onto a cooled spinning wheel so that it solidifies as a thin flake with a fine, even structure. It is the step that follows melting in making a sintered magnet.

See alsoHydrogen decrepitationRare earth alloySintering

Read moreHow rare earth magnets are made

The tracker's five labels for a federal support item. Closed or awarded: money invested or an award made. Announced: publicly announced or approved; closing not confirmed here. Conditional commitment: a commitment that depends on conditions being met. Non-binding letter: a letter of intent or interest with no binding obligation. Under review: an application in technical or credit review.

A conditional commitment, a letter of interest or a selection is not money paid. State and local items are tracked apart from federal support and never added to its totals.

See alsoLetter of interestConditional commitmentSelected for award negotiation

Read moreGovernment support trackerMethodology

The grinding and machining waste left when magnet blocks are cut and shaped. It is the main recycled rare earth stream today, and the Department of Energy estimated it at 9% of world NdFeB magnet output in 2020.

See alsoEnd-of-life magnetsHydrogen processing of magnet scrapMagnet block

Read moreWhat can be recycled to recover rare earths

SourceDepartment of Energy: Rare Earth Permanent Magnets, Supply Chain Deep Dive Assessment (Feb 2022)

The waste left after valuable minerals are taken out of ore, kept in piles or ponds. Old tailings can still hold rare earths, so they are a feed for some plans, and they can hold radioactive material and water that has to be managed.

The USGS describes rare earths in apatite in the tailings at Pea Ridge in Missouri and at Mineville in New York.

See alsoUnconventional sourceBy-productSource material

Read moreWhat environmental issues rare earth mining raises

The document that S-K 1300 requires a mining company to file with the SEC to support its resource and reserve disclosure, usually as an exhibit to a 10-K or 8-K. It is signed by the qualified person and describes the deposit, the plan and the economics.

NioCorp's 2026 technical report summary for Elk Creek was filed as exhibit 96.1 to its SEC filing.

See alsoS-K 1300Qualified person10-K

Read moreHow big and how rich US deposits are

SourceeCFR: 17 CFR 229.1300, the S-K 1300 definitions for mining registrantsNioCorp 2026 technical report summary, exhibit 96.1 (SEC)

Narrow veins and dikes rich in thorium and rare earths, mostly found by radioactivity surveys in the 1950s. They are small and radioactive, so thorium is often the main commodity in old records and the main problem in new plans.

Lemhi Pass on the Idaho and Montana line is a thorium and rare earth vein district.

See alsoSource materialMonaziteHistoric or prospect deposit

Read moreLemhi PassWhat distinguishes each type of deposit

A tonne is a metric ton, 1,000 kg; a short ton is 0.9072 tonnes. Mt is million tonnes, kt is thousand tonnes, and t/yr or tpa is tonnes per year, the usual unit for a plant's capacity. Most reports use tonnes; MP Materials reports in short tons.

MP Materials' 28.96 million short tons of reserves at Mountain Pass is about 26.3 Mt.

See alsoNameplate capacityContained TREO

Read moreTerms in a resource estimate

A mine, project or mill with its own profile page and a pin on the map. This directory tracks 14. Other US deposits, such as the USGS's historic districts, are described without being tracked.

See alsoProducingDevelopmentExplorationHistoric or prospect deposit

Read moreRare earth mines in the USMap of tracked sites

The electric motor that turns the wheels of an electric vehicle. Many use NdFeB magnets, and the high-temperature grades made for them need the most dysprosium and terbium.

See alsoNdFeB magnetDysprosium and terbium

Read moreHow much dysprosium and terbium a magnet needs

Total rare earth elements

Total rare earth elements: the weight of the rare earth metals without the oxygen. The oxide of each rare earth weighs roughly 14% to 27% more than the element, so a TREE figure is smaller than the TREO figure for the same rock.

La Paz in Arizona reports 391 ppm TREE, not TREO, so it cannot be compared directly with projects that report TREO.

See alsoTREOGrade

Read moreWhy two estimates for the same deposit differ

Total rare earth oxide

Total rare earth oxide: the weight of all the rare earths in rock or a product, counted as oxides. It is the usual way a grade is quoted, and a resource estimate multiplies tonnes of mineralized material by the TREO grade to get contained oxide.

Reports differ on whether scandium is counted, so check the definition. The richest tracked US deposit, Mountain Pass, is about 5.98% TREO (OSTI).

See alsoREOTREEGradeContained TREOBasket

Read moreTerms in a resource estimateIs a higher TREO grade always better?

Rare earths recovered from material that was not mined for them: coal and coal ash, mine waste and tailings, bauxite residue. The grades are low, but the material is already mined, so some projects count the mining cost as paid.

Brook Mine in Wyoming is a coal mine with rare earth plans, and the Department of Energy selected five coal-waste pilots in Jul 2026 for award negotiation.

See alsoTailingsBauxite residueAsh basisBy-product

Read moreUnconventional sources of rare earths in the US

US Geological Survey

The US Geological Survey, the federal agency whose Mineral Commodity Summaries are the main public source for US rare earth production, imports and prices. This directory uses the 2026 edition. The USGS also describes the historic US deposits listed here.

See alsoNet import relianceOSTI reviewEarth MRI

Read moreSources

SourceUSGS Mineral Commodity Summaries 2026

The date through which this directory re-checked the facts on a page against their sources. The latest such date is Oct 1, 2026, and facts that changed after it may not be reflected.

See alsoConfidence grade

Read moreMethodology: how often facts are re-checkedUpdates log

A right to buy shares at a set price. A warrant is not ownership until it is exercised, so a stake that includes warrants is larger on paper than what is held.

The Department of War holds a warrant for 11,201,659 more MP Materials shares, priced at $30.03.

See alsoGovernment equity stake

Read moreHow much of MP Materials the government owns

A yttrium phosphate (YPO₄) with 52% to 67% rare earth oxide. The heavy-rare-earth and yttrium mineral, named at Round Top and Bokan Mountain.

No primary US production; yttrium-rich xenotime occurs in the monazite concentrates produced in Florida (USGS 2026).

See alsoHeavy rare earths

Read moreXenotime and the US projects that name it

Two elements that are not lanthanides but are counted as rare earths because they occur in the same ores. Yttrium: ceramics and phosphors. Scandium: aerospace alloys and solid oxide fuel cells (USGS).

China has licensed exports of both since Apr 2025. The USGS says no fully commercial US facility could separate or refine yttrium in 2025 and that scandium was not commercially mined or recovered.

See alsoRare earth elementsLanthanides

Read moreUS producers of yttrium and scandium

SourceUSGS Mineral Commodity Summaries 2026: YttriumUSGS Mineral Commodity Summaries 2026: Scandium

A yttrium-bearing calcium fluoride ((Ca,Y)F₂) with no oxide range in the USGS table. The yttrium fluoride at Round Top, which holds 15 of the 17 rare earths.

Not produced in the US. Round Top, Texas, is in development.

See alsoHeavy rare earths

Read moreRare earth minerals in the US