The Martian soil examined by the Chemistry and Mineralogy (CheMin) instrument on NASA's Curiosity rover shows the diffraction signature, or "fingerprint," of the mineral olivine, shown here on Earth in the form of tumbled crystals about a quarter-inch (several millimeters) in size. The semi-precious gem peridot is a variety of olivine.

NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the project for NASA's Science Mission Directorate, Washington, and built Curiosity and CheMin.

For more information about Curiosity and its mission, visit: http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl .