Indeholder "Introduction", " The Agate Enigma", " Etymology of 'Agate'", " Agates Throughout History", "Quartz and Chalcedony", " What is an Agate?", " Quartz", " Chalcedony", " Chert and Jasper", " Chalcedony's Colors", "Agate Basics", " Agates", " Geological Settings", " Agates of Different Environments", " The Vesicle and the Nodule", " Structures Within Agate", " Band Composition", " Colors and Their Causes", " Agates of the World", " A Picture of an Agate", "Lake Superior Agates", " The Big Lake", " Midcontinent Rift", " Glaciers", " Rock Formations of Lake Superior", "Distribution", " Where and Why", " The Path of the Glaciers", " The Many Agates of Lake Superior", "Finding and Identifying Agates", " Identifying Agates", " How to Find Agates", " Non-Agates", "Formation Theories", " Decoding Agate Formation", " Chalcedony Formation Theories", " Chalcedony and Opal", " A Third Theory", " Recent Findings", " A History of Agate Formation Theory", " Haidinger and Noggerath", " The Twentieth Century", " Raphael Liesegang", " Disproving Liesegang", " Contemporary Agate Research", " Chemical Reactions in Agates", " Eckart Walger", " Accumulation Theory", " Walger's Theory", " Benefits and Criticisms", " Pros and Cons of the Inflow Theory", " Differentiation Theory", " Problems with the Theory", " Pabian and Zarins", " Criticisms", " Pros and Cons of the Gel Theory", " Difficulties with Both Theories", " Accepted Aspects of Agate Genesis", "Source of Silica", " The Origin of the Silica", " Possible Sources", " Conclusion", "Infiltration Channels", " In or Out?", " Structure of Infiltration Channels", " Theories of Channel Formation", " Examples from Lake Superior", " Summary", "Concluding Agate Formation", " A Depolarization of Theories", " The Authors' Approach", " Toward a Definitive Theory", "Post Formation", " Entombed in Rock", "Agate Varieties", " Why Varieties?", " Problems with Definitions", " 'Fakes' and Polishing Artifacts", "Adhesional Banded Agate", "Banded Quartz Agate", "Eye Agate", "Floater Agate", "Agate Geode", "Gravitationally Banded Agate", "Skip-an-Atom Agate", "Vein Agate", "Whorl Agate", "Inclusions and Replacements", " Introduction", " Primary Variations", "Copper Replacement Agate", "Crystal Impressions", "Dendritic Agate", "Fragmented Membrane Agate", "Jasp-Agate", "Mineral Inclusions", "Moss Agate", "Plume Agate", "Sagenitic Agate", "Stalactitic Agate", "Tube Agate", "Color Variations", " Introduction", " Primary Variations", "Colored Macrocrystalline Quartz", "Paint Agate", "Rare Coloration", "Surface Colorations", "Weathering", " Introduction", " Primary Variations", "Brecciated Agate", "Faulted Agate", "Peeled Agate", "Ventifacts", "Water-washed Agate", "Final Topics", " Odd Agates", " 'Clamshells'", " Iris Agate", " 'Scrambled' Chalcedony", " Liesegang Kings", "Before and After", " Working with Agates", " Carving and Shaping", "What is an Agate?", " Conclusion", "Glossary", "References and Recommended Reading", "Index", "About the Authors".

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