Primary Uses
Betavoltaic nuclear batteries, Industrial thickness gauges, Radioluminescent light sources
Scarcity & Economic Profile
Crustal Abundance
~0
Primary Economic Driver
Lab research (radioactive)
Geological Scarcity
Supply Risk
Primary Mining Countries
Primary Processing Countries
Sources - Crustal Abundance
- Rudnick, R. L., & Gao, S. (2003). Composition of the Continental Crust. Treatise on Geochemistry, 3, 1-64.
- Taylor, S. R., & McLennan, S. M. (1985). The Continental Crust: Its Composition and Evolution. Blackwell Scientific Publications.
- Wedepohl, K. H. (1995). The composition of the continental crust. Geochimica et Cosmochimica Acta, 59(7), 1217-1232.
- U.S. Geological Survey. (2026). Mineral Commodity Summaries 2026. U.S. Department of the Interior.
Short Description
Promethium is the only rare earth element with no stable isotopes - every form is radioactive. The longest-lived isotope (Pm-145) has a half-life of just 17.7 years, meaning virtually none survives from Earth's formation. At any given moment, an estimated 500-600g exists across the entire planet as a trace product of spontaneous uranium fission. It is never mined. Commercial Pm-147 is produced either as a nuclear reactor fission byproduct (separated from spent fuel rods) or by neutron irradiation of Nd-146 in a reactor. Its primary application is betavoltaics - converting beta radiation directly into electricity for long-life atomic batteries once used in cardiac pacemakers (pre-1970s, before lithium cells) and still used in precision instruments, guided systems, and remote sensors. It is also used in industrial beta-ray thickness gauges for measuring thin films and materials, and historically in radioluminescent paint for military instrument dials before tritium alternatives became standard.