"Mars Violet is the modern name for the dark violet synthetic reds made during the early 20th century to today but a natural version of this colour has been used since antiquity. The clays that make this violet colour were always very rare compared to other natural iron oxides and it is not until the Greco-Roman world that it is commonly seen in art. The latin name for the colour was caput mortuum which literally translates as ???the head of the dead??? and probably refers to a belief that it is similar to the colour of blood in corpses. Despite this macabre name it has been a well liked pigment whenever it has been available because it extends the range of earth colours into the violet.
During the Renaissance and until the 20th century it was often included with all the dark reddish iron oxide colours that were darker than Venetian Red and was called Indian red. The rarity of the deepest violet versions of the pigment relegated it to a very minor role in art until the 20th century when usage expanded as the synthetic version came on the market. While it is still not used in as great a quantity as other red oxides it has a unique colour that is very useful for artists. For a start it is the perfect colour from which to make the natural colour of lips. No other pigment is as perfect for that job. It can also be useful for the earthy violet colours which can sometimes appear in skin colours in certain lights.
The dull earthy nature of this violet is surprisingly useful for landscape artists too. It is the ideal base from which to make the dusky colours found in may flowers or in evening landscapes when moody reddish violets envelope the earth. Mixed with white and Ultramarine it makes the perfect muted mauves that are common everywhere in nature due to atmospheric effects. Since Mars Violet is absolutely permanent it can be used in all techniques with confidence. Realistically Mars Violet is used almost exclusively for making violet colours but considering it is a one trick pony it sure does that one job extraordinarily well. Those artists who only use earth colours plus Cobalt Blue, Titanium White, and Mars Black find that Mars Violet becomes one of their most useful colours. That is because violets are so common in nature. Mixing Mars Violet with Cobalt Blue gives beautiful deep royal purples and the admixture of Titanium White will then reduce it to an infinity of soft mauves. Warmer reddish violets come from mixing with a soft creamy yellow like Naples Yellow Light or with Permanent Light Violet. it sounds very simple and it is, yet this can be enough to get the myriad soft violets in a Hans Heysen landscape oil painting or the distant hills of a Namitjira watercolour. Those artists were capable of pure poetry in paint and Mars Violet is capable of all the poetic subtlety required for such artwork.