Classification of the nonmetallics

A rational classification is a prerequisite for the systematic study of the geology of the nonmetallics. Neither the conventional treatment of the subject in standard references, nor a strictly genetic classification, is considered satisfactory for this purpose, Several criteria, primarily economic, are set forth, by which the nonmetallics are subdivided into two major groups, the industrial rocks and the industrial minerals. Further subdivision within each group is on the basis of origin. A proposed classification is presented and briefly discussed.