Spherules at Gale Crater - Sol 139 (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)

Caption NASA:"This image from the Right Mast Camera (MastCam) onboard the NASA - Curiosity Mars Exploration Rover shows roughly Spherical Features, which are VERY similar to the ones found by the Mars Exploration Rover Opportunity in the Meridiani Planum Region of Mars. These "Gale Crater's" Spherules are apparently common in this Stratigraphic Unit, informally "Sheepbed"; a Stratigraphic Unit which defines the lower part of the sequences of Strata exposed in the area known as "Yellowknife Bay". These Spherical Features have been interpreted as "Concretions": a definition which implies that they have formed in Water that percolated (---> the movement and filtering of fluids through porous materials) through the Sediment. Curiosity's MastCam obtained these images on the 139th Martian day, or Sol, of the Rover's Surface Operations at Gale Crater (such as December, 25th, 2012)".