When a rose-colored meteorite was found in the Sahara Desert in 2022, no one knew how old it was or where it came from. Not until NASA-funded scientists age-dated its minerals did they realize the nearly 2-pound (800-gram) rock was a piece of Mars that formed more than 4.1 billion years ago, making it one of the oldest Martian meteorites ever found. Named Teghaza 001 after the salt plain in Mali where it was discovered, the meteorite is one of roughly 435 from the Red Planet.

In a paper published Thursday in Science, researchers offered an initial characterization of Teghaza 001, providing a rare snapshot of Mars’ ancient crust and formation. What scientists learn from future studies could help answer many questions, including how water and rocks interacted on ancient Mars.…