Towards systematics of calcite biocrystals: insight from the inside

Abstract

Biocrystals of calcite are frequent as they are employed by many phylae of organisms in shells, eggshells, teeth, spines or sensoric apparatus. The calcite phase in these materials occurs in a range of constitutions, from polycrystalline fabrics to “single-crystals”. We demonstrate systematics of calcite biocrystal architectures, from the hybrid composite mesocrystal fibres of brachiopod and mollusc shells, via the submillimeter-sized hybrid composite crystal aggregates formed by mesocrystal fibres with both morphological co-orientation and lattice co-oriäentation, to more complex purpose-oriented multiplex äcomposite crystals of echinoderm teeth, which feature a high degree of single-crystal-like 3D orientational correlation of microstructural elements of different morphology and composition. These systematics rely on observations by electron backscatter diffraction (EBSD) and TEM