Minerals are the most common materials on Earth. Scientists have found more than 3,000 types of minerals on the planet. Discover more about this feature of the natural world in Minerals, a title in the Focus on Earth Science series. Focus on Earth Science is a series of AV2 media enhanced books. A unique book code printed on page 2 unlocks multimedia content. These books come alive with video, audio, weblinks, slideshows, activities, hands-on experiments, and much more.