The search for the philosopher's stone, the agent for transmuting base metals into gold, laid the groundwork for modern chemistry. The origin, both in time and place, of the stone, which was known by innumerable fanciful names, is obscure. Writers disagree in describing its powers, properties, and color, as well as the time required for transmutation. In addition to its transmutatory power, the stone was believed to have the properties of a universal medicine for longevity and immortality (potable gold, aurum potabile). -- AATA