Mol wt about 3300. Blue coloring matter from various species of lichens, particularly Variolaria, Lecanora, and Roccella. Habit. Scandinavia, shores of Mediterranean, Azores, California, East India, Madagascar. Constit. Chiefly azolitmin and erythrolitmin combined with alkalies: lecanoric acid, orcein, erythrolein. Manuf almost exclusively in Holland. Structure studies: Beecken et al., Angew. Chem. 73, 665 (1961). Contains in small amounts α,β,γ-amino and hydroxyorcein.