Do all rocks have iron in them?

Iron is a metal that we dig out of the ground and use to make everything from kitchen knives to skyscrapers. Most of the iron we use comes out of rocks. But do all rocks have iron in them? We asked geochemist Kelsey Woody to help us find the answer.Got a question that’s totally metal? Send it to us at BrainsOn.org/contact, and we’ll help iron out the answer!