Martian dust appears on the surface of a penny, brought along with the Curiosity rover and photographed by the <a href='http://mars.nasa.gov/msl/mission/instruments/cameras/mahli/' target='_blank'>Mars Hand Lens Imager</a> on October 2. The image of the 1909 coin is at the highest resolution possible for the high-powered camera -- 14 micrometers per pixel (a micrometer is about .000039 inches).