Purple is a colour that occurs rarely. In heraldry it is also known as 'pourpre'.
The origins of purple in heraldry are rather complicated, as initially only red was known. In the Middle Ages, red was used as an unmixed, pure, mineral-based colour derived from cinnabar or red lead, for example for painting. Various dye plants were used for dyeing textiles. However, the shade of red varied depending on which dye plant was used. These could include: woodruff (for a dusky pink), madder (a plant, Latin: Rubia tinctorum, also known as dyer’s red or dyer’s madder, for a medium red, light red or wine red), cherry tree bark, sorrel seeds, beard lichen (for an orange), buckthorn, hibiscus blossoms, blueberries, blackcurrants, lingonberries, sandalwood (for a pink). Purple and carmine, as animal-derived and expensive dyes, are also included here.
The differences in colour between painted pigments and dyes derived from plants or animals are particularly striking in the case of red. It becomes clear that, before the age of industrialisation – with its chemical possibilities – it was virtually impossible to achieve any kind of standard, and it is easy to understand why so many different shades of red emerged.
It is likely that purple found its way into heraldry as a particularly noble and expensive shade of red, with all shades ranging from red to blue being classified as purple. There are also regional variations, such as 'morado' (mulberry-coloured), which entered Spanish heraldry via the Kingdom of León.
Purple is regarded as noble and sublime. Over the centuries, it has retained its status as the colour of rulers – whether spiritual or secular. Many kings wore purple cloaks, had – and still have – purple caps in their crowns, and also carried purple banners.
In black-and-white depictions of coats of arms or three-dimensional representations of coats of arms carved in stone, purple is rendered as fine left diagonal lines. Purple is associated with the planet Mercury and the gemstone amethyst. It is regarded as a noble, regal colour.
In colour psychology, purple is said to have a mediating effect.
