In this book two renowned experts share their lifelong passion for geodes and their extensive knowledge of world-class geode deposits as they present the latest theories on the formation and occurrence of these amazing mineral gifts of nature. Visit the geode mines of Northern Mexico and Southern Brazil with Brad Cross. Learn the geode mining process and how the astonishing treasures hidden inside are uncovered. Travel with June Culp Zeitner as she explores vast geode deposits throughout the Midwestern U.S. that provide a recorded history of the ancient seas that once covered the land. Discover Florida's ocean harvest of unparalleled agatized geodes. Meet the close cousins of geodes--thundereggs, septarians and concretions. See over 140 full-color photos of geodes that defy description!