Biominerals tune their properties not only by a distinct hierarchy of nano- to microstructures but also by a purposeful orientation of the crystalline material. This allows an optimal exploitation of the mineral’s anisotropic properties. As shown for various biomineral examples, the texture control is typically rationalized by a classical templating action of a bioorganic scaffold which selectively nucleates a given crystal plane. However, we will present a second mechanism by which a distinct crystal orientation in a bioinorganic solid-state material is accomplished. A case study on bivalve shells reveals that selective and systematic crystal lattice tilting and twisting can excerpt a dynamic texture control, allowing crystal co-orientation as a dynamic respond during biomineral growth.
We show further that this crystal lattice bending is caused by intracrystalline organic matrices incorporated in the biomineral due to its nonclassical crystal growth mode giving rise to a granular nanocomposite structure. By a biomimetic in vitro mineralization exploiting nonclassical crystallization and pseudomorphic transformation, we are capable to mimic this peculiarly complex crystallinity in thin calcium carbonate films which show an identical granular nanocomposite structure. These findings allow us to identify a fundamental process-structure-property relationship in biominerals which may spark new design routes to biomimetic smart materials.