The alchemical vessel stands as one of the most philosophically dense symbols in the depth-psychological corpus, functioning simultaneously as literal laboratory apparatus, mystical container, and psychological metaphor. Jung’s treatment, elaborated across Psychology and Alchemy, Alchemical Studies, and the Collected Works, insists that the vas is not merely a retort or flask but a ‘mystical idea, a true symbol’: it must be round or egg-shaped in imitation of the spherical cosmos, and it is interchangeable with its own contents — water, fire, Mercurius — such that distinctions between container and contained dissolve into a single arcanum. Dorn’s specification that the vessel be fashioned from a ‘squaring of the circle’ underscores its role as the site where opposites are reconciled and the body raised toward spirit. Abraham’s Dictionary maps the vessel’s shifting nomenclature across the stages of the opus — coffin, grave, den, house, rock, glass — demonstrating that the name changes as the matter within transforms. Hillman redirects the symbol toward an imaginal psychology of containment, reading the vessel’s material properties — glass, clay, metal — as modes of psychological attention and secrecy. Edinger translates the sealed vessel into the therapeutic frame: wounded ego, contained process, guarded disclosure. Campbell and von Franz emphasize its womb-like, cosmogonic dimension. The central tension in the literature runs between the vessel as concrete operational container and as a boundless, self-identical mystical totality.