Ancient texts speak of a strange and valuable metal known as orichalcum. The mystical material was often dismissed as a fantastical invention – until they discovered a large cache of the stuff in the Mediterranean Sea. Orichalcum’s name is derived from the Greek for "mountain copper.” One of its most prominent mentions comes in the legend of Atlantis by Plato, in which it is described as “more precious [...] than anything except gold.” The dialogue, called Critias, explains how the mythical citadel of Atlantis was adorned with walls, pillars, and floors that were coated in orichalcum, endowing the building with...