Martian blueberries

Martian blueberries

Fig. 8.24 . This microscopic image taken from Opportunity shows sphere-like grains dubbed "blueberries" that fill a depression near the landing site of the Mars Exploration Rover in Meridiani Planitia. The spherical structures are concentrations of the mineral hematite formed in liquid water about 3.7 billion years ago. (Courtesy of NASA/JPL/Cornell U./USGS.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University