Photographs organized visually by their subject's color with a thumb tab index for quick and easy identification. 850 pages - 7-3/4" tall x 9" wide (open) The text provides descriptions of 200 minerals (including 20 classified as gemstones) and 40 rocks, as well as descriptions of the natural environments where they occur. GREAT VALUE Field Guide to Rocks & Minerals - $19.95 Item - B160 Field Guide to Rocks & Minerals by the National Audubon Society The first all-photographic field guide features 794 full-color images of all the important rocks, gems and minerals of North America, showing their many variations of color and crystal forms.   16th Printing - March 1998