NASA’s Perseverance rover is on the hunt for gems
NASA/JPL-Caltech/ASU/MSSS
NASA’s Perseverance rover has discovered precious stones embedded within Martian pebbles. These stones are composed of corundum, a mineral known as ruby or sapphire based on the metal traces it contains.
Ann Ollila from Los Alamos National Laboratory in New Mexico, along with her team, identified signs of corundum using the rover’s SuperCam instrument on a rock named Hampden River. SuperCam employs various methods to determine a material’s composition, including two lasers to either vaporize its surface or induce luminescence, followed by two cameras to analyze the light emitted. The tests on Hampden River yielded results almost identical to those from lab-measured rubies, suggesting the presence of tiny corundum grains within the rock.
As Perseverance continued its journey along the edge of Jezero crater, it left Hampden River and came across another pebble, named Coffee Cove, which also showed indications of corundum. A similar finding was made with a third rock called Smiths Harbour. Ollila presented these findings at the Lunar and Planetary Science Conference in Texas on March 16.
These gemstones have never been observed on Mars before, and their formation is likely different from that on Earth. “Corundum is typically associated with tectonic activity on Earth, requiring a silica-poor, aluminium-rich environment,” Ollila explained during her presentation. Mars lacks Earth-like plate tectonics, making the discovery of corundum there unexpected. It is believed that the Martian corundum formed when meteorites impacted the surface, causing heat and pressure on the dust.
Allan Treiman from the Lunar and Planetary Institute in Texas, who was not part of Ollila’s team, expressed surprise during the conference. “In retrospect, it might not be so surprising, given the aluminium-rich outcrops and impacts on the planet, but it was still shocking to see this,” he remarked.
The corundum grains are extremely small, less than 0.2 millimeters across, making it impossible to determine from images whether they are rubies or sapphires or to visualize their appearance to the human eye.
“I would love to pick one up and analyze it to see if it appears red—it’s quite disappointing that all we can see is this white pebble,” Ollila noted. Nonetheless, when struck by the SuperCam laser, the grains shone brightly.
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