"A comprehensive new approach to the evolution of thundereggs, how they are deposited and filled. Written for geologists, collectors, laymen, the lapidary arts and rockhounds"--

Robert Colburn’s main model of geode/thunderegg formation based on his lifetime study and mining of geodes. Colburn, being dyslexic, the editor teamed up to fully review and edit his CD draft book and notes, and update it. The original CD book is in poor editorial condition due to his dyslexia. The editor and publisher is a geologist, who helped him with the text. This took place while Colburn was still alive, taking two years. While they last, signed cover pages by Colburn are included with the book, since it is spiral bound, the covers were signed separately. About 250 were signed. Colburn is now deceased and in keeping with his wishes, updates are edits of errors, and when the editor has specific infrared spectroscopy information to identify structures speculated about, that is noted. The content style is unchanged.