Liver of sulfur
Liver of Sulfur is a poorly defined mixture of potassium sulfide, potassium polysulfide, potassium thiosulfate, and probably potassium bisulfide. Synonyms include hepar sulfuris, sulfur, sulfurated potash and sulfurated potassa.
Liver of sulfur is mainly used in metalworking to form a patina, turning copper alloys brown or black.