A detailed atomic force microscopy study has been performed on the open-framework, microporous material silicalite. Emphasis has been placed on determining the effect of supersaturation on the crystal growth process. The relative rates of fundamental crystal growth processes can be substantially altered by tuning the supersaturation. In this manner, it is possible to, for instance, switch on and off surface nucleation while retaining terrace spreading. This offers a potential mechanism by which it might be possible to control important crystal aspects such as defect density and intergrowths.