Dan R. Lynch

Have you ever wondered about the Earth, how it was formed, what is under the dirt? Are you fascinated by rocks and minerals, mountains and rivers? This book takes you into the earth and provides hands on activities to help you better understand our amazing planet.
The author provides simple fact filled text and full color pictures, diagrams and drawings to catch the readers attention. The information is up to date and easy to locate with the index, titles and subtitles. The author provides, charts, diagrams and a glossary to further enhance learning. There are also easy to follow directions for several activities to reinforce the text. Young readers in the 3rd through 5th grades who have an interest in geoscience or who need to create a research project will find this book helpful and easy to follow.… (mehr)

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".

Smukke fotografier og nydelige gennemgang af agater.… (mehr)

Another book read that isn't particularly literature. This one, however, is an excellent field guide, with clear pictures of what particularly fine samples look like. The wide majority are only found in the western UP where there is a long history of volcanics, which brings all sorts of fairly rare or at least unusual minerals to the surface. There is one particular vein of granite that has imbedded greenish topaz. It is very specific and singular apparently. There is even a page on 'Junk', which is man made artifacts rolled around on beaches. I wouldn't mind finding a balled up glob of what was once a beer can. There is a bit of humor here and there with lines like, 'Most rock collectors actually would like a lump of coal for Christmas.' There are several pages of different types of agates and pictures of extremely rare crystals. As opposed to most guidebooks, the photographs actually look like something you might find in the field, albeit particularly nice samples, as opposed to a museum or rock shop. There is also an introductory section with everything broken down into color. If it is red, try..., etc., with warnings of radioactive or lead/arsenic/asbestos bearing rocks. Also, the authors repeatedly explain terms each time they come up, like cleavage or tabular or striated. Should be handy, now to find out how comprehensive it is.… (mehr)