The Great Wave off Kanagawa by Hokusai, a famous artwork that makes extensive use of Prussian blue French chemist Joseph Louis Gay-Lussac gave cyanide its name, from the Ancient Greek word κύανος ( kyanos, 'blue/cyan'), because of its Prussian blue color. In German, hydrogen cyanide is called Blausäure ('blue acid'). Prussian blue lent its name to prussic acid (hydrogen cyanide) derived from it. It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system. The therapy exploits the compound's ion-exchange properties and high affinity for certain ' soft' metal cations. In medicine, orally administered Prussian blue is used as an antidote for certain kinds of heavy metal poisoning, e.g., by thallium(I) and radioactive isotopes of caesium. The pigment is used in paints, and it is the traditional 'blue' in blueprints and aizuri-e ( 藍摺り絵) Japanese woodblock prints. It contains variable amounts of other ions and its appearance depends sensitively on the size of the colloidal particles. It is prepared as a very fine colloidal dispersion, because the compound is not soluble in water. Prussian blue was the first modern synthetic pigment.

Turnbull's blue is chemically identical, but is made from different reagents, and its slightly different color stems from different impurities. Prussian blue (also known as Berlin blue or, in painting, Parisian or Paris blue) is a dark blue pigment produced by oxidation of ferrous ferrocyanide salts.

Victoria 2 blood and iron