Turning the most common of minerals into perfection, that was the goal of the medieval alchemist.
The world is made up of four elements: Earth, Air, Water and Fire. These elements interact through four causes: Material, Formal, Efficient, and Final. This was the thought process within the Aristotelian view of the world. Matter was separated into three, consisting of animals, minerals, and vegetables. The main focus within our work is minerals, and to understand minerals we have to understand what was considered the building blocks of these minerals through the theories presented before us.
Sulphur-Mercury Theory
Pioneered by Jabir Ibn-Hayyan, this was the most popular position held within alchemical circles after it reached Europe through a translation of the Book of the Composition of Alchemy done in 1144. Though, it's debated whether or not Jabir Ibn-Hayyam's works were done by one person, and even if any of them actually held that name. This theory posits that mercury and sulphur existed as the two building blocks for the rest of the mineral world, and that while underground they would both mix together in various quantities to form the rest of the metals found under the surface of the world. In this theory, the more balanced the ratios of sulphur to mercury the closer the material was to gold, the pinnacle of alchemical perfection.
Sulphur-Mercury-Salt Theory
This theory, developed in the 1530 text the Opus paramirum by Philippus Aureolus Theophrastus Bombastus von Hohenheim (also known as Paracelsus), views sulphur and mercury as more metaphysical concepts, the elements necessary to all chemical change. It posits that all change, no matter what, relies on three components: A sulphur (the fuel which ignites the change), a mercury (the thing that is changed), and a salt (the byproduct of the change). This theory is actually why, in modern chemistry, any chemical made with an acid-base reaction is called a salt.
Mercury Alone Theory
A fringe train of thought. It posits that mercury within the earth, when subjected to various forces, gets "cooked" into other metals. John Dee, a man who notably held this belief, peddled his theory that stellar rays are what cooked the metal, and what was produced was determined by astrology. The Mercury Alone Theory has a relation to the Metallic Seed theory of metal production, which thought of mercury as a sort of seedbed where metal "seeds" could be planted and turn the mercury into the desired material. This theory was, however, disproven through conclusive testing by Sir Isaac Newton.