Purple/Violet

Purple is derived from the combination of red and blue, it unites red's fiery masculinity with blue's cool femininity.  Purple is often used to represent royalty, imperial power, justice, and/or truth.  Christian references to the color link it with God the Father and royal power.  Dried blood has a purple hue to it, and bruises on the flesh are often purple, in this respect it can be a sign of physical injury.  Information taken from:   Online Symbolism Dictionary

Violet
In colour symbolism, linked with temperance, moderation, spirituality and repentance, or a transition from active to passive, male to female, life to death.  These interpretations are based on the mingling of re (passion, fire or earth) with blue (intellect, water or sky).  Christ and Mary wear violet robes in some paintings of Passion scenes.  In flower symbolism, the small violet is also associated with modesty or humility - the symbolism of violets in paintings of the Adoration, where they refer both to Mary's chastity and to the meekness of the Christ Child.  Wreaths of violets were remembrance flowers in Rome and were worn at banquets to cool the brow.  Information taken from: Dictionary of Symbols by Jack Tresidder

  Songs referenced: 

Father Lucifer
(underlyrics)

Marianne

Purple People

Scarlet's Walk

Take to the Sky
(underlyrics)