philosopher's stone
The legendary alchemical substance said to turn base metals into gold and grant immortality. Often appears in fantasy, mythology, and historical alchemy contexts.
中世の錬金術師たちは賢者の石を追い求めていた。
Medieval alchemists sought the philosopher's stone.
From 賢者 (wise person) + の (possessive particle) + 石 (stone), a calque of Latin 'lapis philosophorum'.