English: As the Mars Exploration Rover Spirit began collecting images for a 360-degree panorama of new terrain, the rover captured this view of a dark boulder with an interesting surface texture. The boulder is about 40 centimeters (16 inches) tall on Martian sand about 5 meters (16 feet) away from Spirit. It is one of many dark, volcanic rock fragments -- many pocked with rounded holes called vesicles -- littering the slope of "Low Ridge." The rock surface facing the rover is similar in appearance to the surface texture on the outside of lava flows on Earth. Spirit took this false-color image with the panoramic camera on its 810th sol, or Martian day, of exploring Mars (April 13, 2006).