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The U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows:Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities...
The porphyritic to seriate-textured quartz monzonite host-rock at Bagdad was changed by hypogene alteration to a granular rock in which the plagioclase became albitic, orthoclase and quartz increased in amount, and hornblende and book-biotite were recrystallized to pale brown leafy biotite. Hypogene sulfides, pyrite and chalcopyrite, were added during the process of alteration...