The amphibole group is extremely important, widespread, and beautiful, with a structure that can accommodate a bewildering variety of compositions and potentially hundreds of unique specimens. This timely volume will allow mineral collectors to understand how the amphiboles are organized and named, and to relate obsolete names to currently accepted ones. Over 140 full-color crystal images help the reader visualize the important structural features that define amphiboles and control their physical properties. This reference also provides information that collectors need to know to better understand the group and to learn what the specimens teach us about geological processes. Structural chemistry and taxonomy of the group is explored as well as formation and geochemistry, explaining the kinds of environments where amphiboles are formed. An entry for each mineral series provides locality information along with identification photos wherever possible, and examples that one might expect to find in the varied locales.