A magic system rooted in transformation, where practitioners turn one substance into another through study, experimentation, and often personal sacrifice.
Alchemy in fiction draws on the real historical tradition of proto-chemistry and spiritual transformation, then gives it teeth. Fictional alchemists transmute materials, brew potions, create homunculi, or pursue the philosopher's stone. What sets alchemy apart from generic magic is its emphasis on process: you don't just wave a wand, you study, experiment, fail, and iterate. It's magic that feels like science, with laboratories instead of temples.
Alchemy gives you a magic system with built-in structure. Because it's rooted in experimentation, it naturally creates scenes of discovery, failure, and incremental progress. That's gold for pacing. It also lets you write magic users who feel like scientists or craftspeople rather than warriors, which opens up character types that pure combat magic doesn't.
The gold standard for fictional alchemy. Equivalent exchange (you can't create something from nothing) drives every plot point, character arc, and moral dilemma.
The Philosopher's Stone is the series' inciting MacGuffin, and potion-making throughout the books functions as the most alchemy-like magic at Hogwarts.
Sympathy and sygaldry function like alchemy with physics, where precise knowledge and technique matter more than raw power.
Alchemy's identity is process. If your alchemist just snaps their fingers and things transform, you've lost what makes alchemy interesting. Show the work: the lab, the ingredients, the failed attempts.
If your alchemist can turn lead into gold, your world's economy should reflect that. Either make it rare, costly, or illegal, or deal with the consequences honestly.
Historical alchemy was as much about spiritual transformation as material change. Even a light touch of this adds depth to your system.
Design an alchemy system with one core rule (like 'equivalent exchange' or 'nothing organic can be transmuted'). Write a scene where your alchemist needs to solve a problem using this system, but the rule makes the obvious solution impossible. Show them improvising within the constraints.