This view from the front hazard-avoidance camera on NASA's Mars Exploration Rover Opportunity shows the rover's arm's shadow falling near a bright mineral vein informally named "Homestake."

This view from the front hazard-avoidance camera on NASA's Mars Exploration Rover Opportunity shows the rover's arm's shadow falling near a bright mineral vein informally named "Homestake." The vein is about the width of a thumb and about 18 inches (45 centimeters) long. Opportunity examined it in November 2011 and found it to be rich in calcium and sulfur, possibly the calcium-sulfate mineral gypsum.

"Homestake" is near the edge of the "Cape York" segment of the western rim of Endeavour Crater.

Opportunity took this image during the 2,763rd Martian day, or sol, of the rover's career on Mars (Nov. 7, 2011).

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