(eg. mortar and pestle, some leaves and hey presto a potion!) cannot be magical.
Nice example of herbology and knowledge how to use them.
Only one problem in this. It depends what potion you are talking about. If it is a potion of healing, which cure you in
unnatural way, then there is
magic in it. There is something unnatural in it, because till this day no one invented such a thing and see how much is known about biology and chemistry at present day. I wrote about this fact in previous post and hoped someone will take it to heart.
In the cherbology and alchemy you are thinking about is nothing unnatural, but then don't expect unnatural things. Only something what sounds unnatural to in game peasant. Also don't mess into this peasant believs about alchemy, which describe unnatural things, but in fact are only fairy tales.
There are things which are rarely hardly explanable to us, players (people who live at present time) and sounding like magic to common peasants in game. There are also things which are really magic in game and unexplanable to us as players (people living at present times, with vast knowledge). The only explanation is in fact magic, which has its story and rules inside game, made up things, which don't exist in real.