| This rock, informally named "Tisdale 2," was the first rock the NASA's Mars Rover Opportunity examined in detail on the rim of Endeavour crater. It has textures and composition unlike any rock the rover examined during its first 90 months on Mars. Its characteristics are consistent with the rock being a breccia -- a type of rock fusing together broken fragments of older rocks. Image credit: NASA/JPL-Caltech/Cornell/ASU |