Curiosity's Potato Chip Crystals: A Week of Geology at the Nazca Drill Site

Curiosity's 49th drill campaign reveals disk-shaped crystal forms in Martian bedrock — the rover now pivots south after a week of laser zapping, UV imaging, and catching Phobos eclipsing the Sun.

For sols 5063 through 5069, Curiosity worked the Nazca drill hole like a field geologist who refuses to leave until every last sample is bagged. The target: disk-shaped crystal forms embedded in bedrock — features the team cheerfully compares to potato chips. Drill cuttings went to the Sample Analysis for Mars (SAM) instrument for chemical breakdown while the rover's other instruments attacked the surrounding terrain from every angle. The crystal forms got the full treatment. ChemCam fired its LIBS laser at multiple individual crystals — "Ahi Veremos," "Colca," "Bermejo" — building depth profiles that reveal compositional layering within each formation. MAHLI, the hand-lens imager on the robotic arm, captured close-ups of the chip-shaped structures, and the team planned nighttime imaging using both white-light and ultraviolet LED lamps to see how the minerals fluoresce. That UV-at-night move is the kind of methodical thoroughness that separates a $2.5 billion rover from a geology field trip. Mastcam spent the week filling out a mosaic of the Nazca near-to-mid-field — building a panoramic map of the site's context so the crystal forms can be understood within their broader depositional environment. The Remote Micro-Imager (RMI) reached out to more distant targets: rock clusters below "Cordillera" ridge and dark lenses beneath a planar surface on "Mishe Mokwa" ridge. Long-distance geology, done from a robot on another planet. Environmental science ran in parallel. Multiple dust devil surveys, horizon movies, and atmospheric zenith movies were collected across the week. And Phobos — Mars' larger, potato-shaped moon — obliged by transiting the Sun. Imaging of the eclipse was prioritized, a dataset that helps refine Phobos' orbital parameters and Mars' rotational state. By Friday's plan, Curiosity was ready to leave Nazca behind. The final sol included a drive back toward its southerly route, resuming the long trek up Mount Sharp. The Nazca campaign — drill hole number 49 — is now in the books, its samples digested by SAM, its crystals zapped, photographed, and illuminated under alien UV light. What makes these chip-shaped crystals interesting is the question they pose about water. Disk-shaped crystal molds in sedimentary rock on Earth typically indicate minerals that precipitated from evaporating water — sulfates, chlorides, or other salts. Characterizing their chemistry through LIBS and SAM gives the team a window into the composition and behavior of ancient Martian water at this specific stratigraphic level of Mount Sharp. Curiosity is now over 5,000 sols into a 90-sol-class design heritage, driving a route up a mountain on Mars with instruments still delivering science. The Nazca stop was a single week in a campaign that has been running for nearly fourteen Earth years.