Thulium

Overview

Thulium is element 69, a heavy rare-earth metal.¹ It is among the least abundant rare earths, with an average crustal concentration of about 0.52 parts per million; for comparison, silver averages 0.075 ppm.²

Thulium's markets are small and specialized. Irradiated thulium is a compact X-ray source for portable medical and dental equipment, and thulium-doped crystals are used in surgical lasers.¹³ Thulium is on the US 2025 List of Critical Minerals and is covered by the heavy rare earths entry on the EU critical raw materials list.⁴⁵

Where it comes from

Thulium is found principally in monazite, which contains about 20 parts per million of it. It is separated from the other rare earths by ion exchange and solvent extraction, and the metal is made by reducing the anhydrous fluoride with calcium or the oxide with lanthanum.¹ The US government records thulium as a potential by-product or co-product of other rare earths, iron ore and heavy mineral sands.⁴

Heavy rare earths such as thulium are generally scarcer than the light rare earths but are elevated in some ores, including ion-adsorption clays.³ Ion-adsorption clay deposits in southern China have been the world's primary source of heavy rare earths.²

The US Geological Survey (USGS) does not report thulium production. For all rare earths together, world mine output was an estimated 390,000 t of rare-earth oxide (REO) in 2025, of which China produced about 270,000 t.⁶ The chart covers all rare earths, not thulium alone.

• China270,000 t · 69%
• United States51,000 t · 13%
• Australia29,000 t · 7%
• Burma22,000 t · 6%
• Thailand4,800 t · 1%
• India2,900 t · <1%
• Madagascar2,700 t · <1%
• Russia2,600 t · <1%
• Other countries4,310 t · 1%

Covers all rare earths combined, in rare-earth-oxide terms; USGS does not publish thulium output by country. World total is the USGS rounded figure; country figures sum to 389,310 t. USGS estimated Burma, Thailand and Madagascar from Chinese import data. Source: Mineral Commodity Summaries 2026: Rare Earths

What it is used for

• Portable X-ray sources. When thulium is irradiated in a nuclear reactor it forms an isotope that emits X-rays, used in portable X-ray devices for medicine and dentistry.¹ USGS lists portable X-rays among the uses of heavy rare earths.³
• Lasers. Thulium is used as a dopant in yttrium aluminum garnet (YAG) crystals for lasers with surgical applications.¹ Industrial and medical lasers are a recognized end use of the heavy rare earths as a group.³

USGS does not publish separate consumption figures for thulium.³

Grades and forms

Thulium is recovered from the other rare earths as a separated compound such as the oxide, which can be reduced to metal with lanthanum.¹ China's October 2025 controls covered thulium metals, alloys, oxides, compounds, mixtures and products containing it.⁷

Trade and policy

The United States relied on imports for all of its heavy-rare-earth compounds and metals in 2025. A significant amount of imported heavy rare earths arrives embedded in finished goods.³

Thulium was not among the seven elements in China's April 2025 rare-earth export controls, but was added later in the year:

While the suspension applies, exports of thulium products are not bound by the specific provisions of Announcement No. 57.⁸ USGS likewise reports that China suspended the October measures for one year.³

This section is factual background, not legal or trade-compliance advice.

Recycling and substitution

Only small quantities of heavy rare earths are recycled, mainly from permanent magnets.³ Substitutes exist for some heavy-rare-earth applications but are generally less effective, and light rare earths can replace heavy ones in several uses.³

Sources

1. Thulium: element information, properties and uses. Royal Society of Chemistry, accessed 2026-10-03. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

2. The Rare-Earth Elements: Vital to Modern Technologies and Lifestyles (Fact Sheet 2014–3078). U.S. Geological Survey, accessed 2026-10-03. ↩ ↩²

3. Mineral Commodity Summaries 2026: Rare Earths (Heavy). U.S. Geological Survey, accessed 2026-10-03. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

4. Final 2025 List of Critical Minerals. Federal Register, accessed 2026-10-03. ↩ ↩²

5. Regulation (EU) 2024/1252 (Critical Raw Materials Act). EUR-Lex, accessed 2026-10-03. ↩

6. Mineral Commodity Summaries 2026: Rare Earths. U.S. Geological Survey, accessed 2026-10-03. ↩

7. China Suspends Export Controls on Certain Critical Minerals-Related Items. Pillsbury Winthrop Shaw Pittman, accessed 2026-10-03. ↩ ↩²

8. China Temporarily Suspends Export Controls on Key Raw Materials Including Rare Earths, Lithium Batteries, and Diamond. CIRS Group, accessed 2026-10-03. ↩ ↩² ↩³