‘Alchemist’ comes from the word ‘alchemy’. ‘Alchemy’ is the medieval science of turning base metals into gold. Someone who practices ‘alchemy’ is called an ‘alchemist’. It also involves sorcery. For example:

The old man was in search of a true alchemist.
I saw an enigmatic hooded Arab with mighty eagle on his shoulder. He was the alchemist I was looking for.
The man has an eye for tracing pure talent from nowhere. He is just like an alchemist who turns everything into gold.