An impure black carbon pigment originally prepared from charred ivory or horns. Ivory black is a fine-grained, intense black pigment. Current formulations of ivory black usually contain a fine grade of animal black with some Prussian blue. Animal black, or bone black, contains about 10% carbon along with 84% calcium hydroxyapatite with smaller amounts of magnesium phosphate and calcium carbonate. Ivory black is a stable blue-black pigment that is denser than carbon black and has a good working quality for oil paints and watercolours. It is listed among the pigments used for colouring stucco marble in the nineteenth and twentieth century. Synonyms: bone black; animal black; drop black; Frankfort black; German black, Pigment Black 9; CI 77267; Paris black; Elfenbeinschwarz (Ger.); noir d'ivoire (Fr.); abaiser. Wittenburg (1999); Museum of Fine Arts, Boston (2000). [J. Cassar, R. de Angelis]