NASA's Curiosity rover has confirmed that the region on Mars it's exploring, called the "clay-bearing unit," is well deserving of its name. Two samples the rover recently drilled at rock targets called "Aberlady" and "Kilmarie" have revealed the highest amounts of clay minerals ever found during the mission. Both drill targets appear in a new selfie taken by the rover on May 12, 2019, the 2,405th Martian day, or sol, of the mission.
This clay-enriched region, located on the side of lower Mount Sharp, stood out to NASA orbiters before Curiosity landed in 2012. Clay often forms in water, which is essential for life; Curiosity is exploring Mount Sharp to see if it had the conditions to support life billions of years ago.

NASA's Curiosity Mars Rover Finds a Clay Cache
The rover recently drilled two samples, and both showed the highest levels of clay ever found during the mission.