For decades, geologists have studied a mysterious substance that makes up more than one-third of our entire planet without having an official name for it.
This scientific blind spot wasn’t due to lack of interest—rather, the mineral exists naturally only in Earth’s lower mantle, a region beginning 650 kilometers below our feet where pressures reach a crushing 240,000 times that of sea-level air.
Any sample brought to the surface would fundamentally transform during its journey upward, making formal classification impossible under international scientific standards.
Yet in a remarkable breakthrough, researchers have finally solved this planetary puzzle by looking not into the Earth, but toward the stars.
Their discovery revealed that this previously nameless substance—now officially christened “bridgmanite”—comprises an astonishing 38 percent of our planet’s total volume, making it the single most abundant mineral on Earth.
The Classification Conundrum
The quest to identify Earth’s most abundant mineral has challenged geologists for over fifty years.
While scientists had strong theoretical models of the lower mantle’s composition, the International Mineralogical Association (IMA) maintains strict criteria for officially recognizing and naming minerals—chief among these being that specimens must be studied in their natural state, not synthesized in laboratories.
This seemingly straightforward requirement presented an insurmountable obstacle for classifying the dense magnesium iron silicate that dominates Earth’s interior.
The lower mantle, stretching from 650 to 2,900 kilometers beneath the surface, exists under such extreme conditions that any mineral sample brought upward would undergo fundamental structural transformations.
“It’s like trying to bring a snowflake into a furnace for study,” explains mineralogist Jennifer Rask of the University of Toronto, who wasn’t involved in the research.
“The very act of bringing the mineral into surface conditions destroys the properties you’re trying to examine.”
For decades, this conundrum left Earth’s most abundant mineral officially nameless, even as scientists continued studying its theoretical properties.
The substance existed in scientific limbo—recognized as real and crucially important to understanding Earth’s structure, yet unable to be formally classified or named under international guidelines.
A Space Solution to an Earth Problem
Here’s what geologists didn’t initially consider: the answer to Earth’s deepest mineral mystery wasn’t buried beneath our feet but had literally fallen from the sky.
While conventional wisdom suggested that nothing could preserve lower mantle minerals during their journey to Earth’s surface, a team led by Oliver Tschauner from the University of Nevada pursued an unconventional hypothesis—that meteorites might offer the perfect workaround to this classification dilemma.
“What makes Tschauner’s approach so brilliant is that it completely inverts how we think about accessing these impossible-to-reach materials,” notes mineral physicist Martin Chen of the Imperial College London.
“Instead of trying to bring deep Earth materials up, his team found samples that had experienced similar conditions elsewhere in our solar system.”
The researchers turned their attention to a specific meteorite that crashed into Australia hundreds of millions of years ago.
This wasn’t just any space rock—it belonged to a rare class of meteorites that had experienced catastrophic collisions while still in space.
During these cosmic crashes, parts of the meteorite briefly endured temperatures around 2,100 degrees Celsius and pressures approximately 240,000 times sea-level atmospheric pressure—conditions nearly identical to Earth’s lower mantle.
Nature’s Perfect Preservation
The extreme collision conditions perfectly mimicked Earth’s lower mantle environment, effectively creating natural samples of the mystery mineral within the meteorite.
But the crucial difference came after formation—these mineral fragments were rapidly cooled in the frigid temperatures of space, essentially “freezing” their atomic structure in place before they could transform into something else.
“It was basically nature doing high-pressure mineral synthesis and then cryogenically preserving the results,” Tschauner explained.
“The meteorite provided what laboratory experiments couldn’t—a way to study the natural mineral without it transforming during analysis.”
Even with the meteorite samples in hand, identifying microscopic fragments of the mystery mineral presented enormous technical challenges.
Traditional mineralogical techniques weren’t sufficient for analyzing the nanoscale crystals embedded within the meteorite’s complex structure.
The breakthrough came through the use of synchrotron radiation—a type of extremely bright, focused X-ray beam produced by particle accelerators.
This technology allowed the researchers to perform high-resolution diffraction analysis that revealed the precise crystalline structure of the mineral fragments without destroying them.
“The synchrotron gave us the ability to examine these tiny grains with unprecedented precision,” said Tschauner.
“We could map the exact positions of atoms within the crystal structure, confirming that this was indeed the natural form of the mineral we had been studying theoretically for decades.”
A Name Five Decades in the Making
With the mineral’s structure confirmed and its natural occurrence documented, Tschauner’s team earned the right to give Earth’s most abundant substance its official name: bridgmanite, honoring Percy Bridgman, the American physicist who won the 1946 Nobel Prize in Physics for his pioneering work in high-pressure physics.
The choice recognizes Bridgman’s fundamental contributions to the field that made this discovery possible.
As the first scientist to develop systematic methods for studying materials under extreme pressures, Bridgman created the experimental foundations upon which all modern high-pressure mineralogy is built.
“Without Bridgman’s work on high-pressure physics, we might still be completely in the dark about the composition of Earth’s interior,” said Tschauner.
“It seems fitting that the most abundant mineral on Earth should bear the name of the scientist who first gave us the tools to understand such extreme environments.”
Rewriting Earth’s Mineralogical Inventory
The official classification of bridgmanite represents far more than just adding another name to textbooks.
It fundamentally alters our understanding of Earth’s composition and highlights how much we still have to learn about our own planet.
Previous research had estimated that approximately 70 percent of Earth’s lower mantle consists of this single mineral.
Given that the lower mantle itself represents a substantial portion of our planet’s volume, simple calculations reveal bridgmanite’s dominance in Earth’s makeup—it constitutes roughly 38 percent of our planet’s entire volume.
“Think about that for a moment,” says geophysicist Sarah Morton of MIT’s Earth Resources Laboratory.
“More than a third of Earth is made of a single mineral species that no human had ever seen in its natural state until recently.
It really puts into perspective how little direct access we have to most of our planet.”
This abundance makes bridgmanite not just another mineral, but arguably the most important one for understanding Earth’s internal structure, dynamics, and evolution.
Its physical and chemical properties largely determine how the lower mantle behaves, affecting everything from heat transfer within the Earth to the movement of tectonic plates on the surface.
Why It Matters
The bridgmanite discovery has profound implications for multiple scientific disciplines.
For geophysicists, understanding this mineral’s properties helps explain how seismic waves propagate through the planet’s interior, providing crucial data for mapping Earth’s internal structure and detecting anomalies.
For planetary scientists, bridgmanite research offers insights into the formation and evolution of rocky planets throughout the universe.
Super-Earths—planets several times more massive than our own—would likely have mantles dominated by high-pressure forms of bridgmanite, with profound implications for these worlds’ geological activity and potential habitability.
“Bridgmanite is probably the most common mineral in rocky planets throughout the cosmos,” explains planetologist Elena Rodriguez of the Max Planck Institute.
“What we’re learning about Earth’s bridgmanite gives us a starting point for understanding these distant worlds.”
The classification also opens new avenues for experimental research.
Now that scientists have confirmed the natural existence of bridgmanite, they can more confidently develop and refine laboratory techniques for synthesizing and studying it under controlled conditions, advancing our understanding of deep Earth processes.
A Humbling Scientific Journey
The bridgmanite story serves as a powerful reminder of both human ingenuity and the limitations of our direct experience.
Despite living on Earth our entire existence, humanity had no name for the planet’s most abundant substance until researchers found a creative solution to what seemed an impossible problem.
“There’s something profoundly moving about finally naming this substance that’s been beneath our feet all along,” reflects Tschauner.
“It connects us to the deepest parts of our planet that we’ll never physically visit but can still come to understand through science.”
The five-decade quest also demonstrates the increasingly interdisciplinary nature of Earth science.
The bridgmanite breakthrough required expertise spanning mineralogy, crystallography, meteoritics, high-energy physics, and computational modeling—fields that once operated largely independently but now regularly collaborate on Earth’s most challenging questions.
As we continue exploring our planet from its highest peaks to its deepest depths, the bridgmanite discovery stands as testament to scientific persistence and creativity.
By looking to the stars to solve an earthly mystery, researchers finally put a name to the mysterious substance that makes up more than a third of our world—hidden in plain sight yet unseen until science found a way to reveal its identity.
Source: Science Magazine
