The nature of the earth's crust, with its specific mineral prevalence, distribution, and association, which dictate the exploitation of metal ores and fossil fuels, were discussed in relation to occupational exposure to inhalants associated with respiratory diseases and malignancies. The exploitation of minerals and fossil fuels by humans were confined to the uppermost earth surface and crust. Some gold mines have been sunk to depths of 4 kilometers, but exploitation to further depths was prohibited by mine air temperatures and humidity. The earth's crust was composed almost entirely of eight elements, the most abundant of which were oxygen and silicon. The ore minerals were ordinarily distributed in trace quantities. The origin and composition of the three generic rock types, igneous, sedimentary and metamorphic rocks, were described. Ore deposits were formed by any earth process involving physical and chemical mechanisms which mobilize and concentrate previously dispersed elements. Quartz (14808607), found in almost every important rock type in the earth's crust, was responsible for the most prevalent type of pneumonoconiosis, silicosis, encountered in a range of occupational settings. The types and locations of important metallic and nonmetallic mineral deposits in the United States were presented. The exploitation of the earth's crust for mineral resources during the twentieth century exceeded the total exploitation since the beginning of civilization resulting increased human exposure to rocks and minerals with a subsequent increase in related diseases. Some of the natural minerals associated with human diseases and their related complexities were summarized. The author concludes that the exploration of the biological effects of mineral ores is in its infancy.