Perfect for mountain climbers and hikers, this valuable reference covers more rocks and minerals in North America than any other available guide. 794 full-color photographs depict all the important rocks, gems, and minerals -- in many variations of color and crystal form -- and the natural environments in which they occur; written descriptions provide information on field marks, similar rocks and minerals, environment, areas of occurrence, and derivation of names. Includes a guide to mineral collecting and a list of rock-forming minerals