NASA’s Perseverance rover has discovered rare chromium-bearing corundum crystals—the mineral family behind Earth rubies and sapphires—inside three separate pale rocks on the rim of Jezero Crater, marking the first time scientists have identified corundum in a Martian setting.
When Perseverance used its laser to examine pale rocks scattered across the rim of Jezero Crater in 2025, the science team anticipated ordinary Martian geology. Instead, spectral analysis revealed mineral signatures that researchers did not expect to encounter on the Red Planet.
The rover identified corundum, the crystalline aluminum oxide material that forms rubies and sapphires on Earth, complete with traces of chromium. The findings were detailed in a study published in Geophysical Research Letters
by a team led by geochemist Ann Ollila of Los Alamos National Laboratory.
How Corundum Appeared in Unexpected Martian Rocks
Corundum is chemically demanding. Its formation requires bulk compositions heavily enriched in aluminum and depleted in silicon, because ambient silicate minerals typically claim available aluminum to form aluminum-silicate rocks like plagioclase feldspar. Yet all three corundum detections by Perseverance occurred inside rocks dominated by plagioclase.
The three rocks—named Hampden River, Coffee Cove, and Smiths Harbour—are pale, plagioclase-rich float rocks found at different locations along the crater rim. Because float rocks are unattached to local bedrock, they may have been transported from elsewhere by ancient geological forces, offering a window into the wider region.
“Very unexpectedly, SuperCam’s TRL analysis of three plagioclase-rich float rocks in the crater rim were found to exhibit clear signatures of chromium-bearing corundum.”
Ann Ollila, Los Alamos National Laboratory
Investigating Ancient Impacts and Mantle Origins Near Jezero
While the findings do not point to sparkling gems scattered across the Martian surface, they raise questions about planetary chemistry. Researchers suggest the corundum could have formed through magma or hot fluid interactions, though Ollila’s team highlights another possibility: the colossal impact that excavated Jezero Crater billions of years ago.
That geological context connects directly to broader modeling efforts regarding ancient impacts on Mars. Planetary scientists from the SETI Institute and three other U.S. institutions used physics software to simulate the Isidis basin impact—a colossal collision roughly 3.9 billion years ago that gouged a scar more than 930 miles across and rained pulverized rock over Northeast Syrtis before Jezero Crater formed.
The simulation tracked individual rock parcels from their starting depths to understand where debris landed. The results indicate that impacts of this scale could reach deep into the Martian mantle and fling dense material onto the surface near Jezero. Rocks squeezed to extreme shock pressures between 6.5 and 8.7 million pounds per square inch carry distinct crystal deformations, giving the rover a clear marker to distinguish mantle debris from surface crust.
The Continuing Quest for Ancient Microbial Life
Corundum and mantle modeling coincide with other high-profile discoveries along Perseverance’s route. On July 21, the rover collected its 22nd rock core sample from an arrowhead-shaped rock nicknamed Cheyava Falls
near the northern edge of Neretva Vallis, an ancient river valley measuring a quarter-mile wide.
Analysis by onboard instruments such as SHERLOC detected organic compounds within Cheyava Falls.
“Cheyava Falls is the most puzzling, complex, and potentially important rock yet investigated by Perseverance.”
Ken Farley, Perseverance project scientist at Caltech
However, researchers emphasize that non-biological processes can also form organic molecules and mineral spots, leaving the definitive origin of Cheyava Falls unverified.
Curiosity Marks Nearly 14 Years on the Surface
While Perseverance investigates the crater rim and river valleys, its predecessor continues working across the planet. NASA released recent photos of the Curiosity rover’s aluminum wheels, showing significant dents, holes, and cracks accumulated over nearly 14 years of driving.
Landed inside Gale Crater on August 5, 2012, Curiosity was originally designed for a two-year mission. Having traveled more than 32 kilometers across sharp volcanic rocks, the rover remains operational, climbing the slopes of Mount Sharp to analyze ancient climate layers, organic molecules, and historical water activity while Jet Propulsion Laboratory engineers actively adjust its route to mitigate further wheel wear.
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