Prussian blue is a deep blue pigment that was first synthesized in the early 18th century. It is made from iron salts and cyanide compounds, resulting in a vibrant color that has been widely used in art and painting. Its chemical formula is Fe₃[Fe(CN)₆]₂, and it is known for its stability and lightfastness. This pigment has applications beyond art; it is also used in various industries, including printing and textiles. Additionally, Prussian blue has medical uses, such as in treating certain types of heavy metal poisoning, particularly thallium and cesium.