This mosaic, featuring the rock target dubbed "Bylot," was acquired by NASA's Mars Exploration Rover Opportunity on sol 194 (Aug. 9, 2004). It consists of four images taken by the rover's microscopic imager. The spherules shown here are less round than the "blueberries" seen previously in "Endurance Crater," perhaps because the minerals coating them are more resistant to erosion. Dark sand is partially covering the rock. The target was in complete shadow when the images were acquired, except for a small area at the upper right, where direct sunlight caused the camera to saturate and excess charge to "bloom" downward into adjacent pixels.