Hematein (US spelling) or haematein is an oxidized derivative of haematoxylin, used in staining. Haematein must not be confused with haematin, which is a brown to black iron-containing pigment formed by decomposition of haemoglobin. In the Colour Index (but nowhere else), haematein is called haematine, a confusing word that wrongly implies that the compound is an amine.