Apatite is a mineral that gives structure to bones and teeth, and can be used to determine where you have traveled based on what you have eaten—apatite records your appetite! Apatite is the most abundant mineral in your body and is composed primarily of calcium (Ca) and phosphate (PO4) [as Ca5(Po4)3(F,OH)] that are bound together in a rigid crystalline framework (Fig. 1). Joined together with collagen (your body’s most abundant protein), tiny apatite crystals provide the stiffness in bones that support your body and the hardness in teeth that allow you to eat tough foods. One reason that we find fossil skeletons of dinosaurs today is because they contain apatite, which is readily preserved for millions of years.