This 3-D image taken by the microscopic imager on the Mars Exploration Rover Opportunity shows a close-up of the center of the rock abrasion tool hole, ground into "Bounce" on the rover's 66th sol on Mars. Features smaller than one-tenth of a millimeter (.004 inches) are visible. The observed area is a little over 3 centimeters (1.2 inches). The canyon-like crack that runs across the bottom half of the image is really only about 2 millimeters (about 0.08 inches) deep. Scientists are currently using a variety of instruments to study the chemical content of the rock.