This animation show the Mars Exploration Rover Opportunity brushing bright materials off a circular patch of the rock dubbed "Mazatzal." The freshly exposed rock was investigated by instruments on the rover's arm on sol 80 (March 25, 2004). On sol 81, Opportunity used its rock abrasion tool, also located on its arm, to grind into the cleaned-off rock. This animation consists of images taken by the rover's hazard-avoidance camera on sol 79.
Image credit: NASA/JPL