What’s that rock? Meteorite? Piece of impact ejecta? Chunk of basalt? And there’s maybe another piece just beyond.
NASA description: This image was taken by Navcam: Right B (NAV_RIGHT_B) onboard NASA’s Mars rover Curiosity on Sol 637 (2014-05-22 17:51:10 UTC).
Sol 637 raw images (from all cameras), and Curiosity’s latest location map.