Natalie Perkins
Will we ever find out what EXACTLY gold is? That's been bugging me as well... it doesn't seem complete.
Brandon Sanderson
I leave gold intentionally vague, I'm afraid, even by the end of book three. I do this in novels, particularly when I feel that I might do more books in a world later on. The events of books two and three don't lend me to spending much time on gold or malatium, so I figure I'll save really digging into them when I can have a character more focused on them. (I'd someday, for instance, like to do a Malatium or gold Misting and see if I can do anything interesting with them.)