The shape development of fluorapatite (FAP)-gelatine nanocomposites is revealed by means of HRTEM investigations starting from molecular dimensions up to the formation of mesoscaled (elongated) hexagonal prisms. The composite nature of the aggregates is proved by IR spectroscopy and by chemical analyses on all states of shape development. The initial states are characterized by triple-helical fiber protein bundles, which are mineralized step-by-step forming and fixing nanoplatelets of FAP in a mosaic arrangement. After being fully mineralized the bundles form elongated composite nanoboards. In the next step of the growth process the boards aggregate to bundles of boards which are in a more or less parallel alignment with respect to each other. By adding up more and more composite nanoboards a critical size is reached and an electric field is developed, which takes over control and directs the further development of the aggregates. The kind of electric-field-directed growth of the elongated polar nanoboards additionally leads to the formation and inclusion of protein nanofibrils into the growing composite aggregate. By this method, cone-like nanofibril structures develop along the long axis of the aggregates accompanied by more perfect parallel alignment of the composite boards within the aggregates. Further shape development is charcterized by adding up composite nanoboards, in particular to increase the third dimension in volume. This thickening process preferably takes place in the middle part of the elongated aggregates and finally proceeds to their basal ends until a perfect hexagonal prismatic seed is formed, which then is ready for further shape development on the micrometer scale.