Have you ever wondered what a crystal is, or how much a carat weighs? Did you know humans can make crystals? Do you know how we use them? Read 'Crystals' to find the answers to these questions and many more. You'll also find a hands-on activity to try at home or at school, as well as a glossary of unfamiliar words, resources to help you locate additional information, and a useful index.Have you ever wondered what a crystal is, or how much a carat weighs? Did you know humans can make crystals? Do you know how we use them? Read 'Crystals' to find the answers to these questions and many more. You'll also find a hands-on activity to try at home or at school, as well as a glossary of unfamiliar words, resources to help you locate additional information, and a useful index.