Alchemy is a philosophical and protoscientific tradition practiced throughout Egypt and Eurasia which aimed to purify, mature, and perfect certain objects. Common aims were chrysopoeia, the transmutation of "base metals" (e.g., lead) into "noble" ones (particularly gold); the creation of an elixir of immortality; the creation of panaceas able to cure any disease; and the development of an alkahest, a universal solvent. The perfection of the human body and soul was thought to permit or result from the alchemical magnum opus and, in the Hellenistic and western tradition, the achievement of gnosis. In Europe, the creation of a philosopher's stone was variously connected with all of these projects.