Original post: BeautifulEvil
I do agree with you that there appears to be some link between alchemy and gnosticism, but there appears to be a link between alchemy and many other traditions of old.
I'm sure this is because alchemy tends to draw its knowledge and teachings from various ancient traditions.
These are a few sayings from the Gospel of Thomas that indicate a link of some sort.
From the Gospel of Thomas:
18. The disciples said to Jesus, "Tell us, how will our end come?"
Jesus said, "Have you found the beginning, then, that you are looking for the end? You see, the end will be where the beginning is.
Congratulations to the one who stands at the beginning: that one will know the end and will not taste death."
22. Jesus saw some babies nursing. He said to his disciples, "These nursing babies are like those who enter the (Father's) kingdom."
They said to him, "Then shall we enter the (Father's) kingdom as babies?"
Jesus said to them, "When you make the two into one, and when you make the inner like the outer and the outer like the inner, and the upper like the lower, and when you make male and female into a single one, so that the male will not be male nor the female be female, when you make eyes in place of an eye, a hand in place of a hand, a foot in place of a foot, an image in place of an image, then you will enter [the kingdom]."
106. Jesus said, "When you make the two into one, you will become children of Adam, and when you say, 'Mountain, move from here!' it will move."
EDIT:
I would also like to add these from the Hermetic Arcanum:
49. Some have sought for the latent Philosophical earth by Calcination, others by Sublimation; many among glass, and some few between vitriol and salt, even as among their natural vessels; others enjoin you to sublime it out of lime and glass. But we have learned of the Prophet that "In the beginning God created the Heaven and the Earth, and the Earth was without form and void, and darkness was upon the face of the Deep, and the spirit of God moved upon the Waters, and God said, Let there be Light, and there was Light; and God saw the Light that it was good, and he divided the light from the darkness, etc." Joseph's blessing spoken of by the same Prophet will be sufficient to a wise man. "Blessed of the Lord be his Land, for the Apples of Heaven, for the dew, and for the Deep that liveth Beneath: for the Apples of fruit both of sun and moon, for the top of the ancient mountains, for the Apples of the everlasting hills, etc.," pray the Lord from the bottom of thy heart (my son) that he would bestow upon Thee a portion of this blessed earth.
73. The generation of the Stone is made after the pattern of the Creation of the World; for it is necessary, that it have its Chaos and First matter, wherein the confused Elements do fluctuate, until they be separated by the fiery Spirit; they being separated, the Light Elements are carried upwards, and the heavy ones downwards: the light arising, darkness retreats: the waters are gathered into one place and the dry land appears. At length the two great Luminaries arise, and mineral, vegetable and animal are produced in the Philosophers' Earth.
This backs up my statement earlier that alchemy draws its knowledge and teachings from various ancient traditions.
At any rate, this is a rather long post, but as always - make of it what ye will.