Fire and flame are perceived to be direct physical manifestations as much as they are symbolic representations of the spark of creation. This link between the realms of the physical and the spiritual has been honored in ritual and ceremony since our most ancient histories. Lighting a candle in ritual is a call to the higher self and forces of creation.
As the different colors we perceive everyday are the direct effect of each color's own unique wavelength, or frequency, within the visible light spectrum - so it is held that each specific color has it's own unique energy. The ancient Greek sophists philosophized over these frequencies; believing there to be a connection between the colors, the musical notes, the known objects in the solar system, and the days of the week.