Step-by-step Questions and Answers with detailed color photographs for easy identification.The Firefly Guide to Minerals, Rocks and Gems is designed for easy and reliable identification of minerals, gems and rocks. The identification process begins with the stone’s streak color, which is how the book is organized: Blue, Red, Yellow, Brown, Green Black and White. Using a sequence of straightforward questions and answers — aided by over 1,000 photographs and drawings — the book narrows down the possibilities among 350 minerals, gems and rocks to reach the conclusive classification.