"This dual image of a Martian rock taken by the ChemCam instrument aboard the Curiosity rover shows a rock at the ""Rocknest"" area on Mars before it was interrogated with ChemCam's high-powered laser (left) and after interrogation by 600 laser blasts (right). The crosshairs in the darkened portion of the image at right shows where the laser beam penetrated to a depth of at least 1 mm as a result of the repeated shots. The ChemCam laser vaporizes a small amount of material that can be read by a spectrometer to determine the target's composition."