This false-color image taken by the panoramic camera on the Mars Exploration Rover Spirit shows a close-up of the rock dubbed "Pot of Gold" (left), which is located near the base of the "Columbia Hills" in Gusev Crater. Scientists are intrigued by this unusual-looking, nodule-covered rock and plan to investigate its detailed chemistry in coming sols. This picture was taken on sol 159 (June 14, 2004).