In a groundbreaking new study, scientists have found compelling evidence that Earth’s core may be slowly leaking precious metals—including gold—into the layers above it, challenging long-held beliefs about the core’s isolation from the planet’s mantle.

The research, published in Nature on May 21, is based on an in-depth, three-year geochemical analysis of volcanic rocks from Hawaii. These basaltic rocks, formed by plumes of molten magma rising through Earth’s mantle, contain tiny traces of heavy elements such as ruthenium—a rare platinum-group metal. This discovery supports a theory that Earth’s molten metallic core may not be as sealed off as previously thought.

“For decades, it was just a hypothesis that the core could be losing material into the mantle, but our data provides the strongest evidence to date,” said lead author Dr. Nils Messling, a geochemist at the University of Göttingen in Germany.

A Gold Reservoir Beneath Our Feet

Over 99.95% of Earth’s gold, along with other heavy metals like platinum and ruthenium, is believed to be locked away deep in the core. These elements were delivered to the forming Earth via meteorite impacts over 4.5 billion years ago and were drawn into the dense metallic core during the planet’s differentiation.

Now, it appears that a minute portion of this precious cargo is migrating upwards, escaping into the rocky mantle and eventually emerging at the surface through volcanic activity.

“This tells us the core is not as isolated as we once assumed,” said co-author Professor Matthias Willbold. “We now have clear evidence that enormous volumes of mantle material—likely originating near the core-mantle boundary—rise to the surface to form volcanic islands like Hawaii.”

Needle in a Planet-Sized Haystack

To uncover this rare geochemical signature, researchers analyzed basalt samples from Hawaii, including those from the 1959 Kilauea Iki eruption. The rocks were crushed, melted, and chemically treated to isolate traces of platinum-group elements, focusing particularly on ruthenium.

“The mantle itself has virtually no ruthenium—it’s one of the rarest elements in Earth’s crust,” said Messling. “But the core is rich in it. So when we find specific isotopes of ruthenium in volcanic rock, it’s a clear fingerprint that part of that rock originated in the core.”

The ruthenium isotopes they detected don’t match any known meteorites or surface rocks, further supporting the idea that they come from deep within the Earth, where the planet’s oldest and most chemically unique materials reside.

Gold’s Silent Journey

While the idea of gold leaking from Earth’s core sounds like the plot of a science fiction novel, the reality is far less glamorous—at least in the short term. The amount of gold rising from the core through volcanic plumes is incredibly small, practically undetectable without sophisticated instruments. Still, over billions of years, this slow trickle could significantly alter the composition of Earth’s crust.

“If ruthenium is making its way up from the core, then gold is likely doing the same,” Messling said. “It’s chemically similar, and both would follow similar paths.”

Unfortunately, accessing this gold at its source is virtually impossible with today’s technology. The core-mantle boundary lies nearly 1,800 miles beneath Earth’s surface—over 230 times deeper than the deepest borehole ever drilled.

Why It Matters

More than just a treasure hunt, this discovery reshapes our understanding of Earth’s internal dynamics. Geologists have long assumed the dense metallic core and the rocky mantle were like oil and water—separated by density and unable to interact. But this new evidence suggests otherwise.

“It’s fascinating because it tells us Earth’s layers aren’t completely closed systems,” said Helen Williams, a geochemistry professor at the University of Cambridge. “It opens up a new chapter in understanding how our planet evolved and continues to change.”

Other experts echoed the excitement. “This has been debated for years, but this study brings strong evidence that some core material has indeed been leaking into the mantle,” said Dr. Jesse Reimink of Pennsylvania State University.

A Long-Term Leak

According to Messling, the process of gold and other metals leaking from the core likely spans hundreds of millions to a billion years. And while the effects are subtle on the surface, scaled over geologic time, they could contribute to the precious metal reservoirs we mine today.

“It’s possible that some of the gold we’ve collected on Earth’s surface actually started its journey from the core,” Messling said. “It’s an idea that’s both humbling and thrilling.”

So, while the notion of mining Earth’s core remains science fiction, this research reveals that the planet may have been offering up bits of its deepest secrets all along—just very, very slowly.