Amazing Agates: Lake Superior's Banded Gemstone by Scott F. Wolter.

Between the covers of Amazing Agates, you’ll discover everything you’ve always wanted to know about Lake Superior’s banded gemstone. Mr. Agate himself, Scott Wolter, will highlight all types of agates, explain features within individual agates and give a brief history of the largest, most famous Lake Superior agates. Scott will even share his best picking locations with you. Ever wonder what your prize agate would rate? Check out the pioneering Scale of Value. Detailed images illustrate every agate, agate type and feature talked about in the book.