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NASA's Perseverance rover has made yet another unusual discovery on Mars, spotting greenish spots inside a rock. The mysterious discovery was made by the rover's SHERLOC WATSON camera that took a nighttime mosaic image of the Malgosa Crest abrasion patch in the "Serpentine Rapids". 

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The photo also shows white and black spots. To see what lies inside the rock, Perseverance made an abrasion patch five centimetres in diameter in a outcrop named "Wallace Butte." The large green spot lies in the upper left portion of the image and is approximately two millimeters (about 0.08 inches) in diameter. 

Oxidized iron is responsible for the colour of rocks on Earth similar to those found on Mars. It is also what makes the blood red. The green tinge is also common in rocks on our planet. They are formed when liquid water seeps through sediment before hardening into rock. A chemical reaction then transforms oxidised iron to its reduced form, lending a green hue to a rock.

Also Read: Life may have flourished on Mars till a few billion years ago

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The reduction reaction can either happen because of microbes or decaying organic matter in the rocks on Earth. Chemical interaction between sulfur and iron can also cause iron-reduction reactions without the help of microorganisms.

However, what caused the green colour in the Martian rocks is a mystery as the rover didn't have much space to safely place its arms holding the SHERLOC and PIXL instruments directly on top of the green spot.

Also Read: Do you see it? Human face spotted on Mars is totally relatable

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Black-and-white striped rock on Mars

The rover recently also clicked an image of a black-and-white striped rock on Mars. It came across the odd rock while climbing the steep slopes of the Jezero Crater and marching towards its rim.

The rock was named Freya Castle and scientists think that as the rover continues to climb up the crater, it might come across more such rocks. It is the only stone of its kind observed on Mars and completely different from the underlying bedrock. Experts think that the rock likely rolled downhill from somewhere higher.