blane
Deep Space Operator
NASA's Mars Exploration Rover Opportunity has found bright veins of a mineral, apparently gypsum, deposited by water. Analysis of the vein will help improve understanding of the history of wet environments on Mars.
http://www.jpl.nasa.gov/news/news.cfm?release=2011-377&rn=news.xml&rst=3220
http://www.jpl.nasa.gov/news/news.cfm?release=2011-377&rn=news.xml&rst=3220