Did you know that sometimes diamonds fall to Earth from space inside rocks called meteorites? Most gemstones are minerals which form in the ground as rock heated in the Earth cools down. As minerals grow, they make regular shapes called crystals. Discover more fabulous facts about gemstones in this comprehensive and accessible guide, which features agate, amber, amethyst, diamond, emerald, jasper, lapis lazuli, opal, ruby and sapphire. Packed with stunning photographs of bright, shiny gems, as well as more practical images of excavation and extraction, this book explains how different environments affect different gemstones and provides a colourful insight into the geology of our world.