Term: Alizarin

A synthetic coal-tar dye used in the manufacture of red pigments. In its crystal form alizarin appears as a reddish-orange and as a brownish-yellow in powder form. It is one of the earliest known dyes. Historically it was obtained from from the roots of the madder plant but is now synthetically derived from anthraquinone.

Alizarin is the main ingredient for the manufacture of the madder lake pigments known to painters as Rose Madder and Alizarin Crimson. Alizarin in the most common usage of the term has a deep red color, but the term is also part of the name for several related non-red dyes, such as Alizarine Cyanine Green and Alizarine Brilliant Blue.