philosophers' stone

noun, Alchemy.
1.
a substance sought by alchemists that would be capable of transmuting baser metals into gold or silver and of prolonging life.
Also, philosopher's stone.
Origin
1350-1400; Middle English
British Dictionary definitions for philosopher's stone

philosopher's stone

noun
1.
a stone or substance thought by alchemists to be capable of transmuting base metals into gold
philosopher's stone in Culture

philosopher's stone definition


The stone or material that practitioners of alchemy believed capable of changing other metals into gold.

Note: Figuratively, the “philosopher's stone” is a substance thought to be capable of regenerating man spiritually.