Scientists have uncovered evidence that precious metals like gold are leaking from Earth’s core into the mantle, ultimately reaching the surface in places like Hawaii.
Using a new method to detect subtle isotopic differences in ruthenium, researchers identified a distinct signal pointing to material from the deep core. This discovery challenges long-held beliefs about the Earth’s interior being sealed off and opens up new insights into how deep Earth processes may be enriching surface geology, even influencing the global supply of critical metals.
Earth’s Hidden Gold: Buried Beyond Reach
Earth’s largest gold reserves are not kept inside Fort Knox, the United States Bullion Depository, stored in bank vaults, or buried in mountain mines. It’s hidden much deeper, far beneath our feet, sealed inside the Earth’s molten core. In fact, over 99.999% of our planet’s gold and other precious metals lie about 3,000 kilometers underground, far beyond human reach.
But now, scientists may have found signs that some of that buried treasure is making its way back up. Researchers from the University of Göttingen have discovered tiny traces of the rare metal ruthenium in volcanic rocks on the islands of Hawaii. This particular type of ruthenium likely originated from the Earth’s core itself. The findings were published in the scientific journal Nature.
Ruthenium from the Core: A Volcanic Clue
Compared to the Earth’s rocky mantle, the metallic core contains a slightly higher abundance of a particular ruthenium isotope: 100Ru. This is because part of the Ru, which was locked in the Earth’s core together with gold and other precious metals when it formed 4.5 billion years ago, came from a different source than the scarce amount of Ru that is contained in the mantle today.
These differences in 100Ru are so minuscule that they were previously undetectable. Now, new procedures developed by researchers at the University of Göttingen have made it possible to resolve them. The unusually high 100Ru signal they found in lavas on the Earth’s surface can only mean that these rocks ultimately originated from the core-mantle boundary.
A Breakthrough in Isotope Detection
Dr. Nils Messling, at Göttingen University’s Department of Geochemistry, explains: “When the first results came in, we realized that we had literally struck gold! Our data confirmed that material from the core, including gold and other precious metals, is leaking into the Earth’s mantle above.”
Core-Mantle Mixing: A Dynamic Earth
Professor Matthias Willbold, at the same department, adds: “Our findings not only show that the Earth’s core is not as isolated as previously assumed. We can now also prove that huge volumes of super-heated mantle material – several hundreds of quadrillion metric tonnes of rock – originate at the core-mantle boundary and rise to the Earth’s surface to form ocean islands like Hawaii.”
Precious Metals from the Deep
This means that at least some of the precarious supplies of gold and other precious metals that we rely on for their value and importance in so many sectors such as renewable energy, may have come from the Earth’s core. Messling concludes: “Whether these processes that we observe today have also been operating in the past remains to be proven. Our findings open up an entirely new perspective on the evolution of the inner dynamics of our home planet.”
Reference: “Ru and W isotope systematics in ocean island basalts reveals core leakage” by Nils Messling, Matthias Willbold, Leander Kallas, Tim Elliott, J. Godfrey Fitton, Thomas Müller and Dennis Geist, 21 May 2025, Nature.
DOI: 10.1038/s41586-025-09003-0
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