This image taken by the panoramic camera on the Mars Exploration Rover Spirit shows a close-up of the rock dubbed "Pot of Gold," located near the base of the "Columbia Hills" in Gusev Crater. The rock's nodules and layered appearance inspired rover team members to investigate the rock's detailed chemistry, which revealed hematite. Further investigation may reveal whether water was involved in the formation of that hematite, or whether the hematite formed in dry conditions. This image was taken on sol 164 (June 19, 2004).