Rare earth minerals
Xenotime in the US: where it is mined and which projects depend on it
Xenotime, YPO4, is the yttrium phosphate that most often carries the heavy rare earths, and in the US it is named at Round Top in Texas and Bokan Mountain in Alaska and occurs in the monazite concentrates produced in Florida. It is 52% to 67% rare earth oxide, with up to 5% uranium oxide (USGS).
No US mine produces it as a primary product. 2 tracked projects name it, the USGS describes 3 more districts, and its 2002 database reports it at 19 sites in 13 states. OSTI says recovery from xenotime has been demonstrated commercially to some extent, but the USGS says no fully commercial US facility could separate or refine yttrium in 2025.
Verified through Oct 1, 2026
- US mines producing it
- 0As a primary product (USGS)
- Tracked projects naming it
- 2Of 14 on the map
- Rare earth oxide in the mineral
- 52% to 67%USGS, Table 3
- USGS 2002 sites naming it
- 19In 13 states
- US import reliance for yttrium
- 100%USGS 2026
The definition
What is xenotime?
Xenotime is the yttrium phosphate mineral, YPO4, usually an accessory in acidic and alkaline rocks. It is 52% to 67% rare earth oxide, and the USGS says deposits enriched in heavy rare earths most commonly have it as the principal rare earth mineral.
- Formula
- YPO4
- Oxide
- 52% to 67% rare earth oxide and 0 to 5% uranium oxide; the USGS gives no thorium figure (Table 3).
- Forms
- Usually as an accessory mineral in acidic and alkaline rocks, and sometimes as a detrital grain; it can look like zircon, but it is softer and has perfect cleavage (USGS).
- Carries
- Yttrium and heavy rare earths such as dysprosium and terbium.
The comparison
Which US projects and districts depend on xenotime?
2 tracked US projects name xenotime and the USGS describes 3 more districts. Round Top is in development; Bokan Mountain is exploring. The table sets out each one's deposit, resource figures and next step; filter by kind or state.
| Project or district | Kind | Status | Deposit and minerals | Resource figures | Next step or latest activity |
|---|---|---|---|---|---|
| Round TopTexas | Tracked project | Development | Peralkaline rhyolite; yttrofluorite and xenotime; heavy-rare-earth rich | Older estimate (Texas Mineral Resources): 359 Mt measured and indicated at 639 ppm REO plus 675 Mt inferred at 638 ppm | Definitive feasibility study due Q4 2026; commercial production target 2028 |
| Bokan MountainAlaska | Tracked project | Exploration | Peralkaline complex; allanite, bastnaesite, monazite, xenotime; heavy-rare-earth rich | Ucore Apr 2026 estimate: 5.15 Mt at about 0.58% TREO (0.4% cut-off), about 29,900 t contained; totals summed from the published categories (OSTI review earlier listed 5.23 Mt at about 0.65%) | No mine schedule; Ucore focuses its near-term US effort on a Louisiana processing complex |
| Music ValleyCalifornia | USGS-described district | Company program | Xenotime in biotite-rich zones of the Pinto Gneiss. Xenotime (yttrium and heavy rare earths). | No resource estimate in the 2010 report. Five 1957 rock chips held 3.5% to 8.8% yttrium. A 1993 compilation lists 50,000 t at 8.6% rare earth oxide, about 4,300 t. | Feb 27, 2026. Dateline Resources (ASX: DTR): Acquired the 57-claim, 1,140-acre Music Valley heavy rare earth project; the deal closed. Planned work is mapping, sampling and geophysics to define drill targets. Total outlay US$1.05M, of which US$1.0M is an equity investment in Fermi Critical Minerals. |
| Pea RidgeMissouri | USGS-described district | Company program | Four rare earth breccia pipes cutting a magnetite and hematite iron orebody, with rare earths in apatite tailings. Monazite and xenotime in apatite. | A 1990 Bureau of Mines report: about 600,000 t of rare earth reserves at 12% oxide in the breccia pipes. The USGS notes the supporting data are missing. | Mar 16, 2026. Caldera Holdings (St. Louis): The owner says it plans to reprocess waste from the old iron mine for rare earths, develop phosphate for fertilizer and later return to underground mining; its chairman says partners are preparing to invest more than $1B. No permit or resource estimate was verified here. |
| Laughlin PeakNew Mexico | USGS-described district | None found | Twenty-nine thorium and rare earth veins in trachyte and sandstone. Brockite, xenotime, crandallite (mostly heavy rare earths). | No estimate. 30 samples held 30 to 24,200 ppm thorium and 147 to 19,030 ppm total rare earths, about 0.018% to 2.34% oxide. | No activity found in the sources checked. |
Nothing matches that search.
Tracked projects are the ones with a profile here; a project is listed when its deposit description names xenotime. USGS-described districts are the ones on the historic deposits page; their resource figures are decades-old USGS estimates made under no modern reporting code, never reserves.
Verified Oct 1, 2026 Every row links to a full profile where one exists.
Download the data: USGS 2002 sites by mineral (CSV)Projects by mineral (CSV)Minerals (CSV)
Where is xenotime found in the US?
Xenotime is named at Round Top in Texas and Bokan Mountain in Alaska, and occurs in the monazite concentrates from Florida's sand operations (USGS). The USGS 2002 database reports it at 19 sites in 13 states, from the Carolina placers to the Mineville iron dumps in New York.
A mention of xenotime at a site is a report that it occurs there, not a resource.
| State | Sites | Sites, with links where this site covers them | USGS deposit types |
|---|---|---|---|
| Alaska | 4 | Bokan Mountain (Ross-Adams), El Dorado Creek area, Mount Prindle (Roy Creek), Port Clarence | 2 alkaline igneous, 2 placer, alluvial |
| Idaho | 3 | Bear Valley, Diamond Creek, Lemhi Pass | 1 metamorphic, 1 other igneous (pegmatites and veins), 1 placer, alluvial |
| North Carolina | 2 | Carolina monazite belt, Marion | 2 placer, alluvial |
| California | 1 | Music Valley | 1 metamorphic |
| Colorado | 1 | Wet Mountains | 1 carbonatite |
| Florida | 1 | Vero Beach | 1 placer, shoreline |
| Illinois | 1 | Hicks Dome | 1 carbonatite |
| Missouri | 1 | Pea Ridge | 1 hydrothermal iron oxide |
| Montana | 1 | Snowbird | 1 fluorite |
| New Jersey | 1 | Scrub Oaks | 1 hydrothermal iron oxide |
| New York | 1 | Mineville dumps | 1 hydrothermal iron oxide |
| South Carolina | 1 | Horse Creek (Aiken County) | 1 placer, alluvial |
| Wyoming | 1 | Bear Lodge Mountains (southern) | 1 carbonatite |
The USGS Open-File Report 02-189 database (Orris and Grauch, 2002) lists the rare earth minerals reported at each site. A mention is a report that the mineral occurs there, not a resource or an ore, and a site counts once, under the first state it names. The download lists every record with its position where the USGS gives a usable one.
Which US projects depend on xenotime?
Round Top in Texas names xenotime with yttrofluorite, and Bokan Mountain in Alaska names it with allanite, bastnaesite and monazite. Both are rich in heavy rare earths: about 72% of Round Top's oxide is heavy rare earths plus yttrium, and 35% to 40% of Bokan's rare earths are heavy (company-reported).
- Development Round Top, Texas Older estimate: 359 Mt measured and indicated at 639 ppm REO plus 675 Mt inferred at 638 ppm. A feasibility study is expected in Q4 2026 and first production is targeted for H2 2028 (company targets).
- Exploration Bokan Mountain, Alaska Ucore Apr 2026 estimate: 5.15 Mt at about 0.58% TREO, with 35% to 40% heavy rare earths (company-reported).
- USGS district Music Valley, California Xenotime in biotite-rich zones of the Pinto Gneiss; five 1957 rock chips held 3.5% to 8.8% yttrium. Dateline Resources bought the claims in Feb 2026 (company-reported).
- USGS district Pea Ridge, Missouri Monazite and xenotime in apatite in breccia pipes of an old iron mine. A 1990 figure of about 600,000 t of rare earth reserves at 12% oxide lacks supporting data, the USGS notes.
- USGS district Laughlin Peak, New Mexico Twenty-nine thorium and rare earth veins with brockite, xenotime and crandallite, mostly heavy rare earths; no resource estimate.
Does the US separate yttrium from xenotime?
No. The USGS says no fully commercial US facility could separate or refine yttrium in 2025, net import reliance is 100%, and China supplied 70% of yttrium imports in 2021 to 2024. Yttrium is about 0.12% of the rare earths in Mountain Pass ore.
Yttrium-rich xenotime is part of the monazite concentrates produced in Florida. China has licensed yttrium exports since Apr 2025, and the White House said after the May 17, 2026 summit that China would address US concerns about shortages including yttrium and scandium; see China's export controls.
- Imports 100% net import reliance China 70%, Germany 11%, Austria 8% and Korea 4% of imports in 2021 to 2024; nearly all derived from concentrates processed in China (USGS).
- US ore Mountain Pass: 0.12% Yttrium is about 0.12% of the rare earths in the Mountain Pass ore, and its production content is not reported (USGS).
- Price Up 42% in 2025 The average price of yttrium oxide rose 42% and of yttrium metal 22% against 2024 (USGS).
- Plans ReElement and USA Rare Earth ReElement lists yttrium oxide among its Marion products, and USA Rare Earth's Less Common Metals in the UK made its first commercial yttrium metal pour in Apr 2026.
Is xenotime radioactive?
Xenotime carries uranium rather than much thorium: the USGS lists 0 to 5% uranium oxide for it and gives no thorium figure, against up to 20% thorium oxide in monazite. The figures are ranges for the mineral worldwide, not measurements at any US deposit.
The NRC and Agreement State licensing page explains when processing uranium- or thorium-bearing ore needs a radioactive materials license.
| Mineral | Formula | Rare earth oxide | Thorium oxide | Uranium oxide |
|---|---|---|---|---|
| Bastnaesite | (Ce,La,Y)CO3F | 70% to 74% | 0 to 0.3% | 0.09% |
| Monazite | (Ce,La,Y,Th)PO4 | 35% to 71% | 0 to 20% | 0 to 16% |
| Xenotime | YPO4 | 52% to 67% | Not given | 0 to 5% |
| Allanite | Ca(Ce,La,Y,Ca)Al2(Fe2+,Fe3+)(SiO4)(Si2O7)O(OH) | 3% to 51% | 0 to 3% | Not given |
USGS Scientific Investigations Report 2010-5220, Table 3. The ranges describe the mineral worldwide, not any one US deposit or plant.
How do you tell xenotime from zircon?
Xenotime is easily confused with zircon because their crystal habit and overall appearance are similar, but xenotime is not as hard as zircon and has perfect cleavage (USGS). It can be yellowish brown to reddish brown with a vitreous to resinous luster, and less often gray, salmon pink or green.
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.
- 5 Bastnaesite in the US The mineral at Mountain Pass, the only US mine that produces rare earths as its main product.
- 4 Monazite in the US The by-product of titanium and zirconium sand mining that feeds White Mesa Mill.
- 4 Allanite in the US The host mineral at Halleck Creek and La Paz: huge tonnage, low grade.
- 5 Rare earth minerals Bastnaesite, monazite, xenotime, allanite and yttrofluorite: thorium, processing and the US projects that name each.
- 22 Historic and prospect deposits USGS-described districts without a profile, with the company activity found since 2024.
- ↑ Rare earth mines in the US The full directory with every status and role in one table.
- Round TopYttrofluorite and xenotime in a heavy-rare-earth-rich rhyolite
- Bokan MountainFour rare earth minerals, 35% to 40% heavy
- China export controlsYttrium is licensed since Apr 2025
- US producers by elementWho could make yttrium and scandium
- Monazite in the USThe concentrates that carry Florida xenotime
- Rare earth mineralsAll five minerals compared
- Historic and prospect depositsMusic Valley, Pea Ridge and Laughlin Peak
- Types of US rare earth depositsWhich deposits hold the heavy rare earths
Questions about xenotime in the US
What is xenotime?
An yttrium phosphate mineral, YPO4, that is 52% to 67% rare earth oxide and the principal rare earth mineral in most deposits enriched in heavy rare earths (USGS).
Does the US mine xenotime?
Not as a primary product. Yttrium-rich xenotime occurs in the monazite concentrates produced from Florida's sand operations (USGS), and Round Top in Texas and Bokan Mountain in Alaska name it but are not producing.
Is xenotime radioactive?
It carries uranium: the USGS lists 0 to 5% uranium oxide and gives no thorium figure. Monazite, with up to 20% thorium oxide, is the thorium-heavy mineral.
Where is xenotime found?
In the US, at Round Top, Bokan Mountain, old districts such as Music Valley and Pea Ridge, and 19 sites in the USGS 2002 database across 13 states. Worldwide, the USGS links heavy-rare-earth-enriched deposits to xenotime.
Why does the US import yttrium?
No fully commercial US facility could separate or refine yttrium in 2025, and nearly all imported yttrium metal and compounds were derived from concentrates processed in China (USGS). China has licensed yttrium exports since Apr 2025.
What is the difference between xenotime and monazite?
monazite is a light-rare-earth and thorium phosphate recovered from sands; xenotime is an yttrium phosphate that carries heavy rare earths and uranium. Both are phosphates and they often occur together.
Which US project has the most xenotime?
The sources checked give no xenotime tonnage. Round Top has the largest resource of the two projects that name it, at 359 Mt measured and indicated plus 675 Mt inferred (older estimate), with about 72% of its oxide heavy rare earths plus yttrium (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 Open-File Report 02-189: rare earth element mines, deposits and occurrences (Orris and Grauch, 2002) Official record
- USGS Mineral Commodity Summaries 2026: Yttrium Official record
- USA Rare Earth Q2 2026 results (SEC) Official record
Tags show what kind of source each link is. How sources are ranked