Amethyst is a kind of quartz, and it's beautiful purple color has made it a desirable gem for thousands of years. It's the presence of iron or manganese may contribute to its awesome color! Today, the purple stones are mined all over the world, and people wear it in all kinds of jewelry. In this book presented by Scientific American, readers learn the geologic process that creates an amethyst among other Earth science and geology information. Interesting fact boxes add even more detail to the main content. Beautiful full-color photographs enhance the understandable text.