Opportunity image: Where’d that Jelly Donut rock come from?

(Real name: Pinnacle Island.) This image from the panoramic camera (Pancam) on NASA’s Mars Exploration Rover Opportunity shows where a rock called “Pinnacle Island” had been before it appeared in front of the rover in early January 2014. This image was taken during the 3,567th Martian day, or sol, of Opportunity’s work on Mars (Feb. 4, 2014). Pinnacle Island, in the lower left corner of this scene, has a dark-red center and white rim, an appearance that has been likened to a jelly doughnut. It showed up in front of Opportunity in an image taken on Sol 3540 (Jan. 8, 2014) at a location where the rock had been absent in an image taken… [More at link]