Curiosity Right Mastcam (M-100)

Sol 431 00:01 Site 20/0764 0431MR0017570000302497E01_DXXX
Dark-toned rock target Marcellus [observations]
Jan 1, 2000 at 11:58:56 AM UTC (approximate)
Credit: NASA / JPL-Caltech / Malin Space Science Systems

Image Source