The element iron reacts very easily with oxygen to form what are called “iron oxides” (iron plus oxygen). Some of these oxides are always kind of crumbly and useless, such as the oxide most of us just call “rust.” But some can be quite useful and even pretty. Hematite can form as a super-shiny metallic mineral that looks like a black mirror. As a result, it’s popular for making beads and other pieces for jewelry. On the other hand, it can be kind of rustlike too, but when it is, it’s a nice dark red color, similar to the color of blood, which, of course, some people may find to not be so nice! In fact, the name hematite comes from the Greek word for blood. People in early civilizations used the rustlike hematite to add color to their pottery, and primitive people used it to make cave drawings and for ceremonial purposes. Hematite occurs not only far away in time, but also far away from Earth. You may have heard or seen that Mars is red, or at least a lot of it is. Well, that’s no coincidence because Mars has a lot of oxidized iron as the mineral hematite on its surface.