The rarest metals on Earth
By RareMetals.net Editorial Team · Published
The rarest stable metals in the Earth’s crust are rhenium and the platinum-group metals (iridium, osmium, rhodium, ruthenium and platinum), followed by gold. Each makes up only a few parts per billion of the crust. Rarer still are radioactive elements such as astatine and francium, which exist only fleetingly in nature. The rare earths are much more common than their name suggests: even the scarcest, thulium, is more than 100 times as abundant as gold.
The rarest stable metals by crustal abundance
| Metal | Symbol | Abundance in crust (parts per billion) | Notes |
|---|---|---|---|
| Rhenium | Re | 0.7 | By-product of molybdenum from copper mines; about 81 tons mined in 2025 (USGS). See rhenium price. |
| Iridium | Ir | 1 | Densest-known element with osmium; spark plugs, crucibles, electrochemistry |
| Rhodium | Rh | 1 | Catalytic converters; the most expensive platinum-group metal in most years |
| Ruthenium | Ru | 1 | Hard-disk coatings, electronics, catalysts |
| Osmium | Os | 1.5 | Very dense; tiny market; toxic oxide |
| Tellurium | Te | 1 | Metalloid; by-product of copper refining; CdTe solar panels. See tellurium price. |
| Gold | Au | 4 | About 3,300 tons mined in 2025 (USGS) |
| Platinum | Pt | 5 | Catalysts, jewellery, hydrogen electrolysers |
| Palladium | Pd | 15 | Petrol-car catalytic converters |
| Silver | Ag | 75 | Far more common than gold |
The rarest elements of all
Radioactive elements with short half-lives are the rarest naturally occurring elements. Astatine is usually named the rarest: less than a gram is thought to exist in the Earth’s crust at any moment, constantly formed and destroyed by uranium and thorium decay. Francium is similarly fleeting. Elements beyond uranium are made in reactors and accelerators and are not found in nature in meaningful amounts.
The rarest rare earth metals
Among the 17 rare earths, the scarcest stable ones are thulium (about 0.5 parts per million), lutetium (0.8 ppm), terbium (1.2 ppm) and holmium (1.3 ppm). That is still hundreds of times more than gold. Promethium is the exception: it has no stable isotopes and is almost absent in nature. See light vs heavy rare earths for abundance figures for all 17.
Rare is not the same as expensive
Price depends on supply and demand, not on abundance alone. Rhenium is rarer than gold in the crust but sells for far less per kilogram, because demand is small. Terbium is hundreds of times more common than gold but costs about a thousand dollars a kilogram because it is concentrated in few deposits and needed for magnets. See the most expensive metals for prices.
Rarest metals FAQ
What is the rarest metal on Earth?
Among stable metals, rhenium, at about 0.7 parts per billion of the crust, closely followed by the platinum-group metals. Counting radioactive elements, astatine and francium are far rarer.
Is rhodium rarer than gold?
Yes. Rhodium is about four times rarer than gold in the crust, and only about 20-25 tons are mined each year, which is why it is usually more expensive than gold.
What is the rarest element on Earth?
Astatine. Less than a gram is estimated to exist in the crust at any time.
Are rare earth metals actually rare?
Not in the crust: cerium is about as common as copper. They are "rare" because they seldom form deposits rich enough to mine and are hard to separate from each other.
Sources: CRC Handbook of Chemistry and Physics (abundance); USGS Mineral Commodity Summaries 2026 (production). General information only.