We are blind to many wavelengths of light. Violet is the shortest wavelength colour still visible to us. But beneath violet lies ultraviolet. We cannot see ultraviolet, but it is visible to some animals, including bees, butterflies and birds.
The first truly violet pigment used by artists was the poisonous and rather weak Cobalt Violet (the name Kobold reputedly coming from German for the goblins or evil spirits that interrupted miners in their search for precious substances).
The complex symbolism of violet seems to reflect its position on the edge of sight. The artist, Kandinsky, writes:
‘Just as orange is red brought nearer to humanity by yellow, so violet is red withdrawn from humanity by blue. But the red in violet must be cold, for the spiritual need does not allow of a mixture of warm red with cold blue. Violet is therefore both in the physical and spiritual sense a cooled red. It is consequently rather sad and ailing.’
Others believe that violet is a colour of spiritual ascension. Wearing violet symbolises transformation or retreat.
This post has now led me on a synchronous leap to my namesake, as violets (the flowers) can symbolise faithfulness or early death. Ophelia wears a ring of violets about her neck in Millais' Ophelia.
See my fiction blog for more on botanical symbolism.
image of the sun in extreme ultraviolet: http://sunearth.gsfc.nasa.gov/sunearthday/media_viewer/flash.html
Kandinsky quote found at this interesting colour site:
For the image shown above and for flower symbolism in Millais' 'Ophelia':