One of Curiosity’s most clever instruments is the “ChemCam” a laser that can shoot rocks from a distance to determine if they are worth further investigation.  How does it work? It uses a well know photonics phenomenon know as LIBS - Laser Induced Breakdown Spectroscopy.  Shooting the rock ablates the surface creating a plasma plume.  The plume can then be analyzed spectroscopically revealing the light signature of the elements contained.  If the sample looks promising, then Curiosity can drive over and drill for further analysis.  Who knows what fascinating discoveries lie ahead?