The Curiosity rover has completed the first x-ray diffraction experiment ever done by a robot (correct me if I'm wrong), showing that a soil sample from the Rocknest locality is composed of olivine, pyroxene and feldsparthe typical mineral ingredients of basalt rock. This is not a surprise, yet that fact itself, the fact that Earthly rocks and minerals are universal, never fails to impress me.
As always, the JPL news release provides nice images, including the diffraction pattern itself, details of the equipment used in this pioneering feat, and, to my joy, a stereopair of the Rocknest site. (UPDATE: I am wrong that it's a stereopair.) That's the age-old technique behind the turn-of-the-last-century amusements that allows your brain to produce a 3-dimensional scene from two photos that are slightly offset from each other. I have a series of stereopairs with the instructions that can teach you the geologist's trick of seeing stereo without a stereoscope.