The pigments and dyes, though they make up only a minor percentage of the lipstick’s composition, are certainly the most important, as they impart the colour of the lipstick. Pigments are coloured compounds that are insoluble, whilst dyes are more commonly either liquids themselves, or soluble. The manner in which they provide colour can also vary. Carmine red, also known as carminic acid, is a common red pigment, which is derived from cochineal bugs, a variety of scale insects that live on cacti. It is prepared by boiling the insect bodies in ammonia or sodium carbonate solution, filtering, and then adding hydrated potassium aluminium sulfate (more commonly known as alum).