Scientists have identified a meteorite discovered in Mali’s Sahara Desert as one of the oldest Martian rocks ever found on Earth, offering new insights into the planet’s geological and water history. Named Teghaza 001, the approximately 800-gram specimen formed more than 4.1 billion years ago and is among just three of the most ancient Martian meteorites identified so far. Researchers found that the rock contains unusual volcanic minerals and zircon crystals that reveal how Mars’ crust cooled and was later altered by underground water around 4.1 billion years ago. The evidence suggests there was an active water cycle on early Mars. Scientists believe further analysis of the rock could reveal more about the planet’s ancient crust and changing environment.