Hepatizon

Hepatizon (Greek etymology: ἧπαρ, English translation: "liver"), also known as Black Corinthian Bronze, was a highly valuable metal alloy in classical antiquity. It is thought to be an alloy of copper with the addition of a small proportion of gold and silver (perhaps as little as 8% of each), mixed and treated to produce a material with a dark purplish patina, similar to the colour of liver. It is referred to in various ancient texts, but no known examples of hepatizon exist today.