In the 46 years that have elapsed since the first edition of this Field Guide, there have been great changes of emphasis in mineral collecting and an unforeseen growth in the number of collectors. Mineral specimens have won popular recognition as objects of beauty and merit, and colorful crystal clusters are now regarded as decorative accessories for elegant homes; their prices have skyrocketed. At the same time, many sources have been depleted, and seemingly inexhaustible deposits have given out, particularly once-promising Mexican sources. New areas in Russia, Africa, and Asia have become significant sources. An increasing recognition of investment values in fine specimens, supplementing the popular demand for colorful accents (usually, and fortunately, examples of little worth to the mineral professional), has driven prices to levels that older collectors find shocking.