Prussian blue is a dark blue solid substance with a coppery luster. It was formerly used in the manufacture of laundry bluing, paint, and blue ink. Aniline products, however, are replacing Prussian blue for these purposes (see Aniline ). The chemical is prepared commercially by mixing ferrous sulfate and sodium ferrocyanide, and then adding sodium chlorate. Prussian blue does not crystallize or dissolve in water. But bases will decompose it (see Base ). A color used in oil painting is also called Prussian blue.
