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 printing. Its chemical formula is Fe₃[Fe(CN)₆]₂, and it is known for its stability and lightfastness. This pigment has played a significant role in various fields, including painting, where it was favored by artists like Vincent van Gogh and Caspar David Friedrich. Additionally, Prussian Blue is used in medical applications to treat certain types of heavy metal poisoning, particularly thallium and cesium.