The substantial contribution of the alkaline igneous rocks to the South African economy is well known and far exceeds their abundance in the geologic record. Most notable are the diamondiferous kimberlites and the rocks of the Palabora Intrusive Suite containing copper, iron, phosphate, uranium, and vermiculite. Kimberlites are also significant because of their deep-seated origin, which provides direct evidence of the nature ofthe upper mantle and crust. This chapter examines the relationship of the kimberlites, carbonatites, olivine melilitites, and salic alkaline rocks in space and time.