Alchemists say that to obtain the philosopher’s stone, the work must begin when the Sun enters the constellation of Aries and the moon enters that of Taurus, because the Sun is exalted in Aries and the Moon is exalted in Taurus. Gemini, the sign that follows, is ruled by Mercury O.
The Sun and the Moon unite to give birth to a child, Mercury. The symbol for Mercury is formed by the disc of the Sun and the crescent Moon, with a plus sign +, the sign for addition, to symbolize their union.
The symbol for Mercury is thus the union of the Sun and the Moon.
The Sun and the Moon give birth to the child, Mercury, the philosopher’s stone. But the philosopher’s stone that the alchemists sought was, in reality, a symbol of sublimation, of the transformation of man who becomes luminous, immortal and free.
The alchemists worked with the Sun and the Moon, that is to say, with the two principles of will and imagination; and thanks to this work with these two principles, they were able to transform themselves and become like the Sun and the Moon – radiant and pure.