The Periodic Table of the Elements

There's an important metric called crustal abundance and that's basically the average rate at which an element exists in the Earth's crust. It's obviously an imperfect standard of data because you might go in your backyard and drill a hole and you will not find that material. But uniformly, however, when you're talking about ore bodies, something that is actually being mined for the sake of extracting the resource, that is generally the average. And so that was the general idea. So I did that for a few years and learned so much about geology and the natural world.