One of the things to keep in mind is I that developed this book before Mistborn was published. I do wonder if sometimes people are going to say, “Oh, he did metals before, and now he’s doing crystals.” But the thoughts arose quite independently in my head. You may know that there is a unifying theory of magic for all of my worlds–a behind-the-scenes rationale. Like a lot of people believe there’s unifying theory of physics, I have a unifying theory of magic that I try to work within in order to build my worlds. As an armchair scientist, believing in a unifying theory helps me. I’m always looking for interesting ways that magic can be transferred, and interesting ways that people can become users of magic. I don’t want just to fall into expected methodologies. If you look at a lot of fantasy–and this is what I did in Mistborn so it’s certainly not bad; or if it is, I’m part of the problem–a lot of magic is just something you’re born with. You’re born with this special power that is either genetic or placed upon you by fate, or something like that. In my books I want interesting and different ways of doing that. That’s why in Warbreaker the magic is simply the ability to accumulate life force from other people, and anyone who does that becomes a practitioner of magic.
In The Way of Kings, I was looking for some sort of reservoir. Essentially, I wanted magical batteries, because I wanted to take this series toward developing a magical technology. The first book only hints at this, in some of the art and some of the things that are happening. There’s a point where one character’s fireplace gets replaced with a magical device that creates heat. And he’s kind of sad, thinking something like, “I liked my hearth, but now I can touch this and it creates heat, which is still a good thing.” But we’re seeing the advent of this age, and therefore I wanted something that would work with a more mystical magic inside of a person and that could also form the basis for a mechanical magic. That was one aspect of it. Another big aspect is that I always like to have a visual representation, something in my magic to show that it’s not all just happening abstractly but that you can see happen. I loved the imagery of glowing gemstones. When I wrote Mistborn I used Burning metals–metabolizing metals–because it’s a natural process and it’s an easy connection to make. Even though it’s odd in some ways, it’s natural in other ways; metabolizing food is how we all get our energy. The idea of a glowing object, illuminated and full of light, is a natural connection for the mind to make: This is a power source; this is a source of natural energy. And since I was working with the highstorms, I wanted some way that you could trap the energy of the storm and use it. The gemstones were an outgrowth of that.