A new rock called Chester Lake identified by NASA's Mars Exploration Rover Opportunity is the new object of speculation that might provide more evidence about the presence of water on the red planet.

This is the second rock on the rim of the Endeavour crater to be explored by NASA, about 3 feet across and lying on the inboard side of a low ridge Cape York.

Rover team scientists chose it for inspection because it is in-place bedrock that appears to be representative of a region of outcrops on the inboard side of Cape York.

Chester Lake differs from the first rock inspected by Opportunity on the Endeavour rim, Tisdale 2, which is a boulder excavated during an impact event that produced a small crater on the rim. Scientists at NASA are planning to use all the data to reconstruct the chemistry, mineralogy and geologic setting of Chester Lake, including evidence about whether or not the rock has any clay minerals in its composition.

Clays form in more neutral, less acidic conditions than the sulfate-rich sandstones we've been looking at. Our hypothesis is that if there are clay minerals, the water was less acidic and therefore more conducive to life, Space.com quoted the rover's deputy principal investigator Ray Arvidson stating.

Check out the latest images of the Chester Lake taken by NASA's Mars Exploration Rover Opportunity.