Wattersite is a rare mercury chromate mineral with the formula Hg<sup>+1</sup><sub>4</sub>Hg<sup>+2</sup>Cr<sup>+6</sup>O<sub>6</sub>. It occurs in association with native mercury and cinnabar in a hydrothermally altered serpentinite. It was first described from Clear Creek claim, San Benito County, California, USA in 1961. It was named to honor Californian mineral collector Lucius "Lu" Watters.