At the heart of alchemy is the practice of transmutation. The ability to transmute substances into other, more useful substances is a valuable skill for any would-be crafter, and it starts with understanding the world around us. Our world is fundamentally made of two things: materia and essentia.
Materia is the physical material that all objects are made from. Although in principle all matter is interchangeable, in practice an alchemist will obtain poorer-quality materia from more common items, and richer materia from rare items. Thus, materia comes in seven grades, from F rank through to A and S rank. There are rumors of an eighth "omega" rank, but no concrete evidence of such a thing has ever surfaced.
Essentia, on the other hand, is the metaphysical essence of an object. You can't interact with it directly; when not bound within an object, it must be dissolved into solution. There are thirteen known types of essentia in this world, named after celestial bodies and related concepts.
Materia gives essentia substance, and essentia gives materia form. By breaking substances down into these two elements and recombining them in different ways, new substances can be formed.
There are three core devices that alchemists make heavy use of in their work. They are the Calcination Furnace, Dissolution Chamber, and Synthesis Table.
The Calcination Furnace uses solid fuel (the same sort you'd use in a regular furnace) to burn off the essentia within a substance, leaving behind only materia.
The Dissolution Chamber does the opposite, using alkahest (the universal solvent) to break down the materia of a substance and leave its essentia in solution.
Finally, the materia and essentia can be recombined in a Synthesis Table with a small sample of a desired substance to create more of the catalyst substance.
The basic versions of these machines only extract half of the theoretical yield of a substance; however, a philosopher's stone would allow upgrading these machines to faster and more efficient versions, if you can get your hands one. It also allows for the creation of a Projection Altar to upgrade materia into higher-ranking forms.
The mod is currently in a transition phase, the wiki is currently down and the repository is a fork. These things will be fixed soon and numerous additions and fixes are (hopefully) incoming.
For now the wiki can be found here.
This mod is originally the wonderful work of the late SynthRose.
Unfortunately Rose is no longer able to contribute to the project but the work lives on.
Originally continued by CumulusMC, we have now taken it on.
If you feel there is anything you can add to the project please submit it in the repository or, get in touch on the discord.