The next stage of the opus is marked by a play of iridescent colors; this is often called the cauda pavonis (peacock's tail). Jung's little black man in the pencil case represents the nigredo condition... the luminous giant radiolarian shining in the forest, however, announces the stage of the cauda pavonis and, according to the alchemists, represents the first sign of the 'resurrection' of the prima materia — an activation of feeling.
Von Franz defines the cauda pavonis as the iridescent stage succeeding the nigredo in the alchemical opus and applies it biographically to Jung's own psychic development, reading a childhood dream-image as its concrete manifestation.
, C.G. Jung: His Myth in Our Time, 1975thesis