NASA's Perseverance rover found an unusual stone on Mars: Check out the 'zebra rock'

Amid the mundane pebbly terrain of Mars' surface, NASA's Perseverance rover recently spotted something remarkable: a strange, striped object that the agency is now referring to as the "zebra rock."

Perseverance, which touched down on the Red Planet in 2021, happened upon the unusual rock while making its slow ascent up the steep slopes leading to the rim of the Jezero Crater. Scientists believe the crater rim may be rife with rocks containing additional clues about past life on Mars – but they may not have expected to find something like this so soon.

The black-and-white striped rock is unlike any seen on Mars before, NASA said this week in a news release.

Here's everything to know about the so-called "zebra rock," as well as other recent discoveries made by Perseverance.

'Zebra rock' named for black, white stripes

The Perseverance rover has spent more than three years on Mars after making a 200-day, 300 million mile journey between July 2020 and February 2021 to reach the Red Plant. The craft's landing site was the bottom of the Jezero Crater, where it has spent the ensuing years scouring the area's rocks and soil for evidence that life once existed on Mars.

Late in August, Perseverance began climbing to the top of the crater, which scientists believe was once flooded with water. It was less than a month into that journey to hunt for more ancient rocks that the rover stumbled upon the "zebra rock."

On Sept. 13, engineers controlling the rover from Earth first noticed the object in the distance due to the odd texture it displayed in low-resolution images on one of the craft's navigation cameras. Engineers initially nicknamed the object "Freya Castle" for a summit located at the Grand Canyon and planned a closer inspection before sending Perseverance on its way.

It wasn't until a few days later when engineers received the beamed data captured by Mastcam-Z cameras high on the rover's mast that they realized just how unusual the rock was. Freya Castle, which is around 20 centimeters across, had a striking pattern with alternating black and white stripes, not unlike a zebra.

NASA: 'Zebra rock' unlike anything seen on Jezero Crater before

While the internet was rife with theories, NASA scientists suspect that either an igneous or metamorphic process could have created its stripes. Since the "zebra rock" is a loose stone separate from the underlying bedrock, NASA scientists believe it likely arrived from someplace else, perhaps having rolled downhill.

But regardless of how it formed or how it ended up in the rover's path, one thing is for certain: The rock has a texture unlike anything the Perseverance team has seen in the Jezero Crater before, NASA said.

"This possibility has us excited, and we hope that as we continue to drive uphill, Perseverance will encounter an outcrop of this new rock type so that more detailed measurements can be acquired," NASA said in a statement.

Perseverance finds signs of life on Mars

The finding is one of several intriguing rocks that Perseverance has spotted during its time on the Jezero crater. 

In July the rover found another unusual Martian rock ringed with black and marked by distinctive white veins and dozens of tiny, bright spots. The discovery, which came as Perseverance explored a quarter-mile-wide valley called Neretva Vallis, could show evidence that life once existed on the Red Planet.

The rock – nicknamed "Cheyava Falls" after a waterfall in the Grand Canyon – has chemical markings that could be the trace of life forms that existed when water ran freely through the area long ago, according to a news release from NASA's Jet Propulsion Laboratory.

The finding was followed the following month by the revelation of liquid water on Mars, which scientists found evidence of buried in cracks several miles under the Red Planet's surface. The discovery served as the "best evidence yet" that Mars still has liquid water in addition to frozen water at its poles, according to the University of California, San Diego's Scripps Institution of Oceanography, which led the research.

The new research was the latest optimistic sign that Mars was at least once habitable and comes at a time as NASA and SpaceX Founder and CEO Elon Musk envision sending humans to Mars – perhaps as early as 2028.

Contributing: Cybele Mayes-Osterman, Doyle Rice, USA TODAY

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at elagatta@gannett.com