MAHLI view of "Gillespie Lake," a coarse sandstone on the edge of Yellowknife Bay, sol 132
Filed under pretty pictures, Mars, Curiosity (Mars Science Laboratory)
Curiosity held its MAHLI camera within 3 centimeters of a ledge on sol 132 to examine its grains up close. The investigation revealed the rock to be a coarse sandstone, made up of cemented grains of a range of sizes. The biggest grains at lower left are about 2 millimeters long, which is larger than sand; technically, they are classified as "granules." The whole view is about 4.3 centimeters wide; at full resolution, it is about 26.1 microns per pixel.
NASA / JPL / MSSS
Here is an annotated version of the image. Also of interest is this MAHLI image, showing the same area of the rock from a greater distance. Here and here are Hazcam views of the position of the arm for both the closer and farther-away photos, and here and here are Navcam views.
Original image data dated on or about December 19, 2012