The species-specific, genetically determined silica frustule of diatoms provides an excellent eukaryotic model for understanding the process of biomineralization and how it is regulated. An effort is made to define molecular events and biochemical constituents in silicon mineralization and to correlate these events with those aspects of silica frustule morphogenesis which have been reported in the published work. A sequential series of steps of silicic acid interaction with the cell is proposed which might be expected for silicon metabolism leading to cell wall formation. A model is put forward that provides for a conceptual framework for continued studies in this area, and provides testable hypotheses which should lead to a greater understanding of biomineralization processes in general and silicification in particular.