Clearcreekite is a polymorph of peterbaylissite. The chemical formula of clearcreekite is Hg¹⁺₃CO₃(OH)·2H₂O. It has a pale greenish yellow color and streak with tabular subhedral crystals and good cleavage on (001). It is transparent with vitreous luster and uneven fracture. Its density (calculated from the idealized formula) is 6.96 g/cm³. The mineral is monoclinic with the space group P2/c. Clearcreekite is an extremely rare mineral from the Clear Creek mercury mine, New Idria district, San Benito County, California. It was probably formed after the alteration of other mercury minerals such as cinnabar. The mineral is named after the locality where it was found.