The philosopher's stone, or stone of the philosophers (Latin: lapis philosophorum) is a legendary alchemical substance capable of turning base metals such as mercury into gold (chrysopoeia, from the Greek χρυσός khrusos, "gold", and ποιεῖν poiēin, "to make") or silver. It is also called the elixir of life, useful for rejuvenation and for achieving immortality; for many centuries, it was the most sought-after goal in alchemy. The philosopher's stone was the central symbol of the mystical terminology of alchemy, symbolizing perfection at its finest, enlightenment, and heavenly bliss. Efforts to discover the philosopher's stone were known as the Magnum Opus ("Great Work").
Mention of the philosopher's stone in writing can be found as far back as Cheirokmeta by Zosimos of Panopolis (c. 300 AD). Alchemical writers assign a longer history. Elias Ashmole and the anonymous author of Gloria Mundi (1620) claim that its history goes back to Adam who acquired the knowledge of the stone directly from God. This knowledge was said to be passed down through biblical patriarchs, giving them their longevity. The legend of the stone was also compared to the biblical history of the Temple of Solomon and the rejected cornerstone described in Psalm 118.
The theoretical roots outlining the stone’s creation can be traced to Greek philosophy. Alchemists later used the classical elements, the concept of anima mundi, and Creation stories presented in texts like Plato's Timaeus as analogies for their process. According to Plato, the four elements are derived from a common source or prima materia (first matter), associated with chaos. Prima materia is also the name alchemists assign to the starting ingredient for the creation of the philosopher's stone. The importance of this philosophical first matter persisted throughout the history of alchemy. In the seventeenth century, Thomas Vaughan writes, "the first matter of the stone is the very same with the first matter of all things".