This substance was first created when contaminated potash was mixed with cochineal by a man named Diesbach.
A substance named for Turnbull has the exact same chemical composition as this substance, although the two were once thought to be distinct. This substance was first created when contaminated potash was mixed with cochineal by a man named Diesbach. People affected by a stolen radiotherapy device in Goiania, Brazil were treated with this substance, since it neutralizes cesium-137. Max (*) Perls developed a staining technique that detects iron by using this substance. Pierre Macquer decomposed this substance into iron and hydrogen cyanide. This substance, which largely replaced the extremely expensive ultramarine, was used to depict the sea in The Great Wave off Kanagawa. For 10 points, name this dye used in the uniforms of Frederick the Great's army.
A substance named for Turnbull has the exact same chemical composition as this substance, although the two were once thought to be distinct.
Prussian blue [or: Berlin blue]