Murex or Tyrian Purple, the most precious colour-fast dye in antiquity—mostly known for the dyeing of textiles with its bright blood-red and violet hues—, served as a symbol of royalty, high prestige and “glorious death” from as far back as the Late Bronze Age. The recognition of purple as a signifier of wealth persisted for centuries, and was employed by Persians, Greeks and Romans as a means of establishing status, of distinguishing kings and emperors, as well as their courts and high officials, both in life and in death (burial shrouds). The use of purple as a codifier of social hierarchy came to a close with the fall of the Byzantine Empire and was substituted thereafter by the red dye produced from the plant Rubbia Tinctorum. However, since antiquity, fascination with the colour purple was intimately linked with the craftsmanship and knowledge required for its manufacture, and with the fact that alchemist experimentations encompassed techniques developed by dyers; dyers, who actually attempted to counterfeit the rare and valuable Tyrian purple dye, as has been made evident through the numerous receipts from the Papyri Holmensis and Leidensis. Purple was said to be endowed with “miraculous” properties, due to the transformation process that occurred during its elaboration phases, described in great detail by ancient authors. More specifically, once the gland is exposed to air, solar irradiation and oxidation lead to the production of several colours that are produced at various stages, colours which include yellow, blue, green, red and violet. The miracle of purple was, therefore, the fact that it appeared to incorporate both darkness and light and, hence, the whole world of colour. The secrets of the science of transformation and the quest for « immortality » were therefore inherent to the very process of producing the purple dye. Archaeological testimonials, such as wall-paintings and precious polychrome objects where purple was used as a pigment, also allow us to broaden our horizons, by means of the elucidation of potential symbolic meanings of the colour purple in antiquity, meanings related mainly to its apotropaic virtues. Finally, information from the Magical Papyri on the use of purple cloth and skin in magical rituals, allow us to further speculate on the possible « mystical » components of purple and its metaphorical connections with the soul.