Unusual rock lying in front of Opportunity on Murray Ridge

This before-and-after pair of images of the same patch of ground in front of NASA’s Mars Exploration Rover Opportunity 13 days apart documents the arrival of a bright rock onto the scene. The rover had completed a short drive just before taking the second image, and one of its wheels likely knocked the rock — dubbed “Pinnacle Island” — to this position. The rock is about the size of a doughnut….. [More at link]