Was pondering over a familiar type character.
She can technically be contrasting schools of magic, although not at the same time. It's like having a glass of water, and needing to empty it, before you fill it with juice, or the like.
Oh, and she can't actually use magic herself. Rather, she's more like a living catalyst/fuel tank(please don't actually call her a fuel tank) for others.
The closest thing she can do in regards to persona magic is to 'crystallize' magic from inside her. The crystal acts as a mini-catalyst/battery. But she still can't use it herself. She can hand it to other people though. Or use it as a physical weapon(like jabbing someone with a shard)