After brushing, a grey circle of rock beneath the ruddy Mars dust is exposed for further analysis. In this photo by Curiosity's Mars Hand Lens Imager (MAHLI), the texture of Mars dust is obvious and fine cracks or seams in "Windjana" can be seen.
"In the brushed spot, we can see that the rock is fine-grained, its true color is much grayer than the surface dust, and some portions of the rock are harder than others, creating the interesting bumpy textures,"
said Melissa Rice
, Curiosity science team member, of the California Institute of Technology, Pasadena. "All of these traits reinforce our interest in drilling here in order understand the chemistry of the fluids that bound these grains together to form the rock."