There are numerous violet pigments on the market, many of great permanence most notably the cobalt and manganese violets. Dioxazine has a large slice of the market, especially in water based media, and in pastels but unfortunately it is not sufficiently light fast in tints and should be avoided. Violet is the one paint color range where the artist can profit from not buying a tube of the color as lively and useful violets can be easily mixed from ultramarine or other blues, and the various reds already in the palette. The one violet color I would buy if I was restricted to just one would be Mars Violet. This pigment makes beautiful soft mauves and lip colored tints, and I would rely on the Ultramarine and Pyrrole Alizarin for brighter violets.