NASA’s Mars Rover Unearths Rare Martian Gemstone After Severe Impact

NASA’s Perseverance rover detected chromium-bearing corundum—the crystalline mineral that forms rubies and sapphires on Earth—inside three distinct rocks within Jezero Crater, according to a study published in Geophysical Research Letters by a research team led by geochemist Ann Ollila. The finding marks the first time corundum has been identified on Mars, presenting planetary scientists with a chemical puzzle because the mineral typically forms in environments rich in aluminum and depleted in silicon, whereas the Martian rocks are dominated by plagioclase feldspar.

Perseverance Rover Discovers Ruby Minerals in Jezero Crater

During targeted operations in 2025, the Perseverance rover used its SuperCam instrument to examine three pale float rocks along the rim of Jezero Crater. Named Hampden River, Coffee Cove, and Smiths Harbour, these rocks were analyzed using time-resolved luminescence (TRL) spectroscopy. According to Ollila and her colleagues, the laser-based analysis revealed clear spectral signatures of chromium-bearing corundum.

Laboratory comparisons performed by the researchers showed striking similarities between the Martian signals and those of terrestrial precious gems. All three rock samples exhibited two prominent luminescence peaks at wavelengths of 692.7 and 694.1 nanometers. These peaks match the exact wavelengths produced when chromium atoms replace aluminum atoms in terrestrial rubies. Furthermore, analysis of the Smiths Harbour sample showed a luminescence glow lingering for about 3 milliseconds, matching the decay time measured in terrestrial corundum.

The Corundum Conundrum: Solving a Martian Chemistry Puzzle

The discovery is remarkable not because of the commercial value of the minerals, but because the formation conditions are difficult to reconcile with Martian geology. Corundum is an aluminum oxide that requires bulk compositions heavy in aluminum and low in silicon. In environments with abundant silicon, silicate minerals typically bind with available aluminum to form aluminum-silicate rocks like plagioclase feldspar.

Because all three corundum detections occurred inside plagioclase-dominated rocks found in separate locations along the crater rim, researchers face a geological dilemma. Because these samples are float rocks—loose chunks resting on the surface rather than attached bedrock—they may have been transported from elsewhere by geological forces, according to the study authors.

How Did Mars Make Ruby-Like Minerals? Impact Heating Examined

To explain how Mars produced minerals that behave like rubies, the research team points to the violent history of Jezero Crater itself. According to Ollila’s team, the colossal impact that carved out Jezero Crater billions of years ago subjected surrounding rocks to extreme heat and pressure. These conditions mirror metamorphic environments deep within Earth’s crust where corundum typically develops. Similar minerals have previously been found in impact-altered rocks on Earth and the Moon.

The research team also notes that past hydrothermal activity in Jezero Crater could have introduced fluids that interacted with the rocks, facilitating the aluminum-rich, silicon-poor chemistry necessary for corundum to form. While other geological explanations cannot be completely ruled out, the impact scenario remains a leading hypothesis among the study’s authors.

The Case for Returning Martian Rocks to Earth

Pinpointing the exact origin of the corundum requires locating the specific bedrock outcrop from which the float rocks broke away. However, definitive answers may require bringing physical samples back to terrestrial laboratories. The study authors emphasize that analyzing a core sample from this outcrop on Earth would allow for vastly more comprehensive tests, helping researchers fully understand the history of Martian mineral formation.

Frequently Asked Questions

Did NASA find actual rubies on Mars?

No. While the Perseverance rover detected chromium-bearing corundum—the exact mineral family and chemical impurity that gives earthly rubies their color—the mineral exists as tiny microscopic grains trapped inside larger rock chunks rather than large, sparkling gemstones.

What instruments did Perseverance use to find corundum?

The rover used its SuperCam instrument and time-resolved luminescence (TRL) spectroscopy, firing a laser to excite atoms within the rocks and measuring the characteristic light they emitted.

Why is finding corundum on Mars surprising?

Corundum typically forms under conditions rich in aluminum and depleted in silicon. Because the Martian rocks where it was found are dominated by silicon-rich plagioclase feldspar, scientists are investigating how these conflicting minerals managed to coexist.