Variation in Mesoscopic Textures of Biogenic and Biomimetic Calcite Crystals

Mesoscale granular textures having a single-crystalline feature are widely observed on various biogenic and biomimetic calcite crystals, although the distribution of organic phases and the magnitude of lattice strain in the textured crystals vary with organism species or growth conditions of the biomimetic process. The prismatic layer of a fan mussel exhibits a relatively homogeneous, low-strain texture consisting of nanoscale grains with discrete organic inclusions; the prism structures of a pearl oyster and an avian eggshell have a high-strain granular texture with localized organic phases. The high-strain granular textures were artificially produced through the mesoscopic dendritic growth of calcite by the physical impedance of a rigid gel matrix. Facet growth of the crystal involving nanoscale segregation of soluble polymers in a supersaturated solution would result in the formation of the low-strain body having mesoscopic textures.