“The discovery of abundant siderite in Gale Crater represents both a surprising and important breakthrough in our understanding of the geologic and atmospheric evolution of Mars,” Benjamin Tutolo, associate professor at the University of Calgary, Canada, and lead author of the paper, said in a statement.

A NASA rover taking rock samples on Mars has uncovered a plentiful mineral that was invisible to orbiters studying the Red Planet from space.

Scientists are eager to find out whether Mars was once capable of supporting life, and according to new Curiosity findings, they're on the right track. NASA's fourth Mars rover has found large carbon deposits within carbonate minerals,