Kermisic acid [CAS: 476-35-7] (CI Natural Red 3; CI 75460) is the oldest dyestuff ever recorded. The name kermes is derived from an Armenian word meaning little worm for which the later Latin equivalent was vermiculus, the basis of the English word vermillion. The dye was obtained from an oriental shield louse, K. ilicis, which infest the holm oak Quercus ilex and the shrub oak Q. coccifera. The dye produces a brilliant scarlet color with an alum mordant. Although expensive, it was cheaper than its rival Tyrian Purple. It was in great demand until the sixteenth century, when it was displaced by carminic acid. The structure of kermisic acid is 1,3,4,6-tetrahydroxy-7-carboxy-8- methylanthraquinone.
