The sphere-like grains or "blueberries" distributed throughout the outcrop can be seen lining up with individual layers. This observation indicates that the spherules are geologic features called concretions, which form in pre-existing wet sediments. Other sphere-like grains, such as impact spherules or volcanic lapilli (fragments of material between 2 and 64 millimeters or .08 and 2.5 inches in maximum dimension that are ejected from a volcano) are thought to be deposited with sediments and thus would form layers distinct from those of the rocks. 3/11/2004 3/11/2004 3/11/2004 the 3.1 millimeter-deep (just over one-tenth of an inch) hole ground by the Mars Exploration Rover Opportunity's rock abrasion tool in the target called "Mojo 2" on "Flatrock" was taken on the 44th martian day, or sol, of the mission. It will help complete the chemical analysis of the lowest layer of the outcrop in the crater where the rover now resides. After a brief brushing on sol 45, the science team plans to place Opportunity's spectrometers on the hole to collect data vital to their understanding of this impressive outcrop. Scientists believe that the spherule or "blueberry" in the upper right area of the circular impression was sliced in half by the rock abrasion tool. "Blueberries" are a known obstruction to the grinding tool that cause it to terminate its sequence. Despite the stall, the rock abrasion tool abraded "Flatrock" for one hour and five minutes, producing a cavity ripe for investigation. 3/10/2004 3/10/2004 3/9/2004 3/8/2004 3/7/2004 3/7/2004 This hole was made by the rover's rock abrasion tool, located on its instrument deployment device, or "arm." The hole is located on a target called "McKittrick" at the "El Capitan" region of the Meridiani Planum, Mars, rock outcrop. It was made on the 30th martian day, or sol, of Opportunity's journey. The grinding process at has generated a significant amount of reddish dust. Color and spectral properties of the dust show that it may contain some fine-grained crystalline red hematite. Courtesy NASA/JPL 3/1/2004 2/29/2004 This hole was made by the rover's rock abrasion tool, located on its instrument deployment device, or "arm." The hole is located on a target called "Guadalupe" at the "El Capitan" region of the Meridiani Planum, Mars, rock outcrop. It was made on the 30th martian day, or sol, of Opportunity's journey. The grinding process at has generated a significant amount of reddish dust. Color and spectral properties of the dust show that it may contain some fine-grained crystalline red hematite. 2/29/2004 The silver colored metal of the ring on the solar abrasion tool is a reddish brown after the dust settled on it, probably from fine-grained hematite. 2/29/2004 2/28/2004 2/28/2004 2/27/2004 2/27/2004 2/22/2004 The image is from the right pan camera, made up of ultraviolet bandwidths. 2/20/2004 2/20/2004