On Mars: Earth-Like Clouds and a New Type of Rock

NASA's Mars rovers sent pictures of Mars' clouds as seen from the planet's surface, some of which looked much like Earthen clouds. More impressively, a rock thought to be billions of years old reveals a mineral composition and structure never seen before! It is believed that the rocks were altered by water, but whether or not the water was liquid is up for debate. The Earth-like clouds are presumed to be made out of ice, because the amount of sunlight that hits the surface during its elliptical orbit (when these images were taken) and near the equator would not allow for warmer temperatures and therefore the clouds would have to be in this phase.

http://www.space.com/missionlaunches/rover_update_041213.html