The aim of this study was to elucidate, at the molecular level, mechanisms of gibbsite crystallization, by measuring directly the growth rates of the individual faces of single gibbsite crystals. It was found that the growth rates of individual crystal faces varied with time, and from one crystal to another. The causes of this variation were also investigated, by examining the effects of solution preparative history. The results imply that the rate limiting steps in crystallization involve the formation of one or more aluminium containing species in solution. Addition of selected organic compounds was found to inhibit the growth of specific crystal faces, which leads to the formation of gibbsite crystals with different morphology; at the same time, they showed a strong effect of inhibiting agglomeration.