" The symmetrical complement of the serpent, then, is the stone as representative of the earth. Here we enter a later developmental stage of the symbolism, the alchemical stage, whose central idea is the lapis. Just as the serpent forms the lower opposite of man, so the lapis complements the serpent. It corresponds, on the other hand, to man, for it is not only represented in human form but even has “body, soul, and spirit,” is an homunculus and, as the texts show, a symbol of the self. It is, however, not a human ego but a collective entity, a collective soul, like the Indian hiranyagarbha, ‘golden seed.’ The stone is the “father-mother” of the metals, an hermaphrodite. Though it is an ultimate unity, it is not an elementary but a composite unity that has evolved. For the stone we could substitute all those “thousand names” which the alchemists devised for their central symbol, but nothing different or more fitting would have been said. "
― C.G. Jung , Aion (Collected Works 9ii)