A Gem of a Find
NASA’s Mars Reconnaissance Orbiter has revealed Martian rocks
containing a hydrated mineral similar to opal. The rocks are light-
toned and appear cream-colored in this false-color image taken by
the High Resolution Imaging Science Experiment camera. Images
acquired by the orbiter reveal that different layers of rock have
different properties and chemistry. The opal minerals are located in
distinct beds of rock outside of the large Valles Marineris canyon
system and are also found in rocks within the canyon. The presence of
opal in these relatively young rocks tells scientists that water,
possibly as rivers and small ponds, interacted with the surface as
recently as two billion years ago, one billion years later than
scientists had expected. The discovery of this new category of
minerals spread across large regions of Mars suggests that liquid
water played an important role in shaping the planet’s surface and
possibly hosting life.
here is the link
http://www.nasa.gov/mission_pages/MRO/multimedia/20081028.html