Alchemy, similarly to herbalism, is a school of magic that heavily relies on the properties of ingredients and items used while performing it. However, unlike herbalism, alchemy doesn't limit itself to one type of ingredients. Alchemists use plants, minerals, animal products and many other things. The most common effect of alchemical work are various potions.
To practice alchemy one must not only have aa good understanding of the magical properties of all the possible ingredients, but also must know the basic of chemistry. Especially, alchemists must know the main principles of chemical experimentation and mixing of substances. Of course, having magical abilities is also necessary. The same as in herbalism, alchemy requires to say an incantation to activate the ingredients' magical properties and make the potion effective.