Rubidium

Overview

Rubidium is a soft alkali metal that ignites in air and reacts violently with water.¹ It is not a major constituent of any mineral. Rubidium is recovered only as a by-product of mining pollucite (for cesium) and lepidolite (for lithium).²

Rubidium is used in small quantities, but some of those uses matter. Rubidium oscillators are frequency references for telecommunications networks and GPS, and the US military time standard relies partly on rubidium fountain clocks.² Rubidium is on the US Final 2025 List of Critical Minerals.³ It is not on the EU's critical raw materials list.⁴

Where it comes from

Lepidolite and pollucite are the main rubidium-bearing minerals in world reserves. Lepidolite can contain up to 3.5% rubidium oxide and pollucite up to 1.5%. Both occur in zoned pegmatites. Rubidium resources exist worldwide, but extracting and concentrating them is mostly too costly.² Potassium minerals and brines are a secondary source.¹

No rubidium production was reported anywhere in 2025, so no production chart is shown. Known ore production in every country stopped within the past two decades. Mining in Namibia ended in the early 2000s. The Bikita Mine in Zimbabwe ran out of pollucite reserves in 2018, and the Sinclair Mine in Australia shipped its last economically recoverable pollucite in 2019. Refined rubidium compounds are thought to be processed in China and Germany from existing stockpiles. Reports indicate that, at current processing rates, commercial ore stockpiles may run out in the near future unless new ore is mined.²

USGS cannot assign reserves to individual countries. It estimates that Australia, Canada, China and Namibia together hold less than 200,000 t of recoverable rubidium materials. Significant rubidium-bearing pegmatites occur in many countries, including Afghanistan, Australia, Canada, China, Namibia, Russia and the United States.²

Several projects that could recover rubidium as a by-product of lithium or cesium mining were at the exploration or feasibility stage in 2025. A Namibian lepidolite project had a JORC-compliant measured and indicated resource of about 23,000 t of rubidium. It went into independent administration at the end of 2024 for lack of financing. In Western Australia, initial tests of an extraction process at the Mount Edon project recovered 97% of the rubidium. The project's inferred resource contains about 7,900 t of rubidium oxide.²

What it is used for

Specialty glass is the leading market. Rubidium carbonate reduces electrical conductivity, which improves the stability and durability of glass in fiber-optic telecommunications networks.²

Other uses include:²

• Timekeeping. Rubidium atomic frequency-reference oscillators synchronize telecommunications networks and are vital for GPS. The US Naval Observatory timescale, the US military frequency standard, uses a network of atomic clocks that includes six rubidium fountain clocks.
• Photoelectric devices. Rubidium is used in magnetometers, motion sensors, night-vision devices, photoelectric cells, photomultiplier tubes and spectrometers.
• Catalysts. Rubidium catalyzes ammonia synthesis, hydrogenation, oxidation, polymerization and sulfuric acid production.
• Medicine. Rubidium-82 is used as a blood-flow tracer in positron emission tomography (PET) imaging.
• Research. Ultracold rubidium atoms are used in research, including quantum computing, which could become a larger use in future.

Rubidium is also used to remove traces of oxygen from vacuum tubes, and rubidium nitrate gives fireworks a purple color.¹

Grades and forms

Rubidium is sold as concentrates, as laboratory and industrial salts, and as high-purity metal in small sealed ampoules.²

Trade and policy

The United States mined no rubidium in 2025, although rubidium-bearing minerals are known in Alaska, Arizona, Idaho, Maine, South Dakota and Utah. It depends entirely on imports. No consumption, import or export data are available, and the sources of US imports have not been reliably known since 1988. Industry information suggests that the United States uses less than 2,000 kg of rubidium a year in end products. The main global producers of refined rubidium compounds are thought to include China, Germany and Russia. There is no government stockpile.²

Recycling and substitution

No rubidium is recycled.²

Rubidium and cesium can often be used interchangeably because their physical properties and atomic radii are similar. Cesium is more electropositive, which makes it preferred for some uses.² Rubidium was studied for ion engines, for example, but proved less effective than cesium.¹

Sources

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

2. Mineral Commodity Summaries 2026: Rubidium. U.S. Geological Survey, accessed 2026-10-03. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹²

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

4. EU critical raw materials. European Commission, Joint Research Centre (RMIS), accessed 2026-10-03. ↩