- © The Mineralogical Society Of America
Non-pegmatitic occurrences of Be minerals constitute a diverse set of geologic environments of considerable mineralogical and petrological interest; they currently provide the majority of the world’s Be ore and emeralds and they contain the greatest resource of these commodities. Of the approximately 100 Be minerals known (see Chapter 1 by Grew; Appendix A⇓), most occur in hydrothermal deposits or non-pegmatitic igneous rocks, where their distribution varies systematically with the setting and origin (Table 1⇓, Fig. 1⇓).
Beryllium minerals are best known from geologic systems associated with felsic magmatism. They also occur in a variety of settings that lack evident igneous associations. Environments range from the surface to the deep crust and host rocks range from feldspathic to carbonate to ultramafic in composition. Genetically related igneous rocks are felsic and share low calcium and high F contents, but are diverse in composition, setting and origin. Compositions range from strongly peraluminous to peralkaline and can be silica undersaturated. Beryllium minerals also occur in metamorphic and basinal environments and are redistributed by surface processes. Table 2⇓ summarizes the types and significance of major groups of occurrences by their lithologic associations. Figure 2⇓ shows the global distribution of some important examples and regional belts. For most types, at least one example has been described in some detail and can be used to help evaluate general patterns; however, …