The small spherules on the Martian surface in this close-up image are near Fram Crater, visited by NASA's Mars Exploration Rover Opportunity during April 2004. The area shown is 1.2 inches (3 centimeters) across. The view comes from the microscopic imager on Opportunity's robotic arm, with color information added from the rover's panoramic camera.

These are examples of the mineral concretions nicknamed "blueberries." Opportunity's investigation of the hematite-rich concretions during the rover's three-month prime mission in early 2004 provided evidence of a watery ancient environment.

This image was taken during the 84th Martian day, or sol, of the rover's work on Mars (April 19, 2004). The location is beside Fram Crater, which Opportunity passed on its way from Eagle Crater, where it landed, toward Endurance Crater, where it spent most of the rest of 2004. A context image is online at PIA05822.

JPL manages the Mars Exploration Rover Project for NASA's Science Mission Directorate in Washington. For more information about Spirit and Opportunity, visit http://marsrovers.jpl.nasa.gov.