A new model of silica's aggregation in rubber, the Hexagon-linking Model, is proposed and tested in this study, using transmitting, scanning and analytical electron microscopy. When wetted in rubber, silica tends to accumulate, by way of hexagonal rings, differently from carbon black; the “wetted” states can be controlled through mixing procedures. The experimental evidence that aggregation of silica (original size of 20 nm) precedes to a final size of 63.8 nm, as compared to a theoretical value of 60 nm, supports the theoretical model. The wetted filler structure can be controlled by the mixing process, and hence desired composite properties can be achieved.