ABSTRACT
The composition of the earth's crust and the distribution of elements can be based only on the best estimates and calculations that can be made with limited evidence. It has been suggested that we probably know less about the composition of the crust of the earth than about the composition of chondritic meteorites. Small but distinct differences in bulk compositions lead geologists to distinguish between continental crust and the crust underlying the oceans. The chapter reviews the geochemical distribution of elements in the earth's crust and the distribution of materials upon which the world's industrial base is founded. One of the most successful of these measures was the Defense Production Act of 1950, which helped meet the nation's need for increased raw materials supplies during the Korean War. South Africa has provided 5 percent or more of the United States' domestic consumption of nine mineral commodities, seven of which appear on the national stockpile list of strategic and critical materials.
