Philosopher's stone
The philosopher's stone is a mythic alchemical substance capable of turning base metals such as lead and mercury into gold or silver; it was also known as "the tincture" and "the powder" as well as "red lion" for gold and "white lion" for silver.
Source: Wikipedia, Philosopher's stone. Text licensed CC BY-SA 4.0. Not endorsed by or affiliated with Wikipedia or the Wikimedia Foundation.