A process for removing mercury from a gas or liquid phase, wherein the gas or liquid phase containing mercury is placed in contact with a composition comprising a precipitated metal sulfide. The precipitated metal sulfide may be made by the process of combining a metal source, sulfide source, and modifier to form the precipitated metal sulfide. The metal source may comprise iron, cobalt, nickel, copper, zinc, zirconium, molybdenum, silver, or gold salts. The metal salt may be selected from metal nitrate, metal sulfate, metal phosphate, metal acetate, metal carbonate, metal hydroxide, metal ammonium carbonate, and metal hydroxycarbonate. The sulfide source is selected from hydrogen sulfide (H2S), carbonyl sulfide (COS), salts of sulfide (S2-), salts of hydrosulfide (HS—), and salts of polysulfide (Sn2-). The modifier may be selected from alumina, silica, aluminosilicate, clay, zeolites, carbon, cement, titania, zirconia.