Alchemy is the ancient Art/Science of attempting to turn physical Lead into physical Gold. It's also an external symbol for an internal spiritual process of transmuting lower denser vibrating materials/consciousness/reality/self into Gold or higher vibrating materials/consciousness/reality/more Self.

Everything that's been going on since 1987, and will continue in humanity and Earth through 2012 and beyond, has been an alchemical process of transformation. Many people call this alchemical process of turning Lead to Gold the 'Ascension process' and a few other things as well. IMO its just different names for the same thing! Spiritual evolution where humanity and Earth go from a lower state like dense 3D Lead into an expanded state much closer to our Higher Selves and Source.....or 5D "Gold".