More amazing Mars images

The amazing new images from Mars just keep on coming. Here are a couple of the latest:
More dust devils! This link shows a sequence of 4 images taken on Spirit's Sol 438, showing a dust devil sweeping across the plain. This is continuing to be a very active dust devil season.


Spirit sees a strange rock in the Columbia Hills


And this is just a very weird rock. What is it? clearly some odd texture and maybe inclusions of a different mineral. Is the rover going in for a close-up look? No, I'm not going to suggest, as some have, that it's a sessile grog, which is apparently something from Larry Niven's Ringworld. If this were on Earth, I would assume it was an archeological artifact of some kind. Ain't Martian geology grand?
(HERE is a larger image that shows this rock in its context).