The philosopher's stone is a mythical stone or elixir that was supposed to turn inexpensive metals into gold and also make humans immortal. Producing such a material was for a long time the main goal of alchemy, but as alchemy evolved into science, the idea went out of favour, and modern scientists do not believe that such a thing has ever existed. The word elixir is derived from the Arabic for philosopher's stone, al iksir.
The philosopher's stone has appeared in works of fiction, most famously in J. K. Rowling's novel Harry Potter and the Philosopher's Stone. This book appeared in the United States under the title Harry Potter and the Sorcerer's Stone, since the publishers felt that a title referring to the "philosopher's stone" would be too esoteric and dull-sounding to appeal to an audience of American youth.