[The text is quite long, but you are able to glean a few details:]
Alchemy, depending on the era and place, generally holds that all things are composed of four or five elements, and that through the use of a universal catalyst called a "stone", any substance can be changed into any other. The creation of the "stone" is done via a long and highly secretive process generally only written down in the most metaphorical and/or symbolic manner, usually in the form of songs, poems, or elaborate illustrations, so as to keep it out of the hands of evildoers.