Scientists using NASA’s Curiosity rover have discovered siderite—an iron carbonate—in the sulfate-rich rocks of Gale Crater, solving a long-standing mystery about Mars’ missing carbonates. This find p

A mineral called siderite found abundantly in rock drilled by a NASA rover on the surface of Mars is providing fresh evidence of the planet's warmer and wetter ancient past when it boasted substantial bodies of water and potentially harbored life.