NASA's Perseverance Mars Rover

Regular readers will remember the "white rocks" that Percy was spotting in little clusters a few months ago, which Mars Guy, among others, was speculating might be quartz. The paper confirms that the first rock examined in detail in the video does contain that mineral, and is not simply another whitish mineral you might expect to find in this environment, like gypsum.

Part of the significance of this mineral being identified is the fact that it seems to comprise most of the rock being analyzed. Quartz-like material ("silica") has been discovered by Spirit, Curiosity and even Zhurong, thousands of km away from Jezero Crater, and Percy itself has already identified some in Sample 24, which we grabbed down in Neretva Vallis. Finding this much silicon dioxide, in multiple forms, in a rock that appears silica-dominated, however, is something new. That's water activity on another level - this is basically very refined silica that nature has cooked up. As the paper mentions, it would be very, very sweet to find an exposure of the source bedrock for these loose pebbles and cobbles, because that stuff we could drill for return to Earth.