1.  A term used in alchemy to describe a substance that is the catalyst in the reaction that transmutes a base metal such as lead into gold. Although called a “stone,” it is probably not a stone at all. The name is used to hide the true nature of the substance. It is also believed to be an elixir that provides perfect health and great longevity or even immortality.

For some, alchemy is a metaphor for increasing spirituality. In this case the philosopher’s stone is the result of purifying the self with years of prayer, meditation, and focusing on the spiritual rather than the physical world.

2.  The goal of alchemical work, a substance that brings good health and long life to those who ingest it.