For something that never existed, the philosopher’s stone has shaped a great deal of history. To people like us — we rational and practical folk of the 21st century — its influence can be hard to comprehend. It was, after all, bad science. Part of its appeal was that it promised so much. Not only did it solve the alchemist’s problem of transmuting base metals into gold, it also provided the elixir of life, even immortality. Numerous civilizations, through a variety of centuries, set out on a quest for the imaginary stone. Was the pursuit a failure? Absolutely. But was it worthless? Far from it.