I was wondering how you were gonna react to that.
Besides what Xantalos said above, magic sometimes has a focus, such as a wand, a staff, scrolls, or runes. Those usually coincide with the idea that raw magic is too wild or powerful to control.
Sometimes magic requires a cost, items rare or expensive that have to be sacrificed or used in a certain way to create the desired effect. Magical potions, for example.
There's also wild magic, magic that isn't used or created specifically by humans or any other sentient races that may exist in a setting, bar druids or elves or something. Wild magic usually permeates a specific location, and does stuff to people or animals that enter it. Will o' wisps in bogs or marshes luring travelers off paths, animals growing smarter, or larger and meaner than their non-magical cousins, even outright magical creatures that don't exist elsewhere, like fairies, djinni/genies, leprechauns, etc. These magical creatures are almost always more powerful than human/mortal magic users.
Sometimes magic is freeform, ie; magic users can do anything within the limits of their imagination, if they have enough magical power or fortitude to do so; other times, magic has constraints or limits placed upon it, like specific words, runes, or spells that have to be used to create the desired effect. Sometimes magic has specific "schools", like elementalism, necromancy, summoning, divination, enchantments, healing, etc. in which magic users have varying degrees of proficiency, or are outright locked into or out of. Other distinctions might be placed upon magic users, like "holy" magic/clerics, whose magic comes from gods, while other mages generally just learn to use magic.
Older magic is generally more powerful than newer magic; such as the wild magic mentioned above, or magical/divine artifacts.
