Scientists viewed a rock like none seen before on Mars when NASA’s Mars Exploration Rover Spirit brushed the surface and took magnified images of this rock dubbed “Wishstone.” The circular area of interest, measuring approximately 5 centimeters (2 inches) in diameter, revealed darker pieces of material randomly distributed within a lighter-colored matrix. The rock has poorly sorted granular material, with grain sizes ranging from fine to coarse and some grains that are very angular in shape. Spirit used its microscopic imager on martian day, or sol, 333 (Dec. 9, 2004) to take the four individual frames that are combined into this mosaic view.