Abstract
In this report, the in vivo mineralization in bivalve shells is reviewed based on the electron microscopic observations of the morphology and surface microtopographs of crystals. The nucleation and growth of crystals in initial mineralization sites where mineral crystals are absent is induced only in the specific organic granule elaborated by the mantle epithelial cells, and then needle crystals grow radially from the center of organic granules to form spherule. However, in additional mineralization during the subsequent growth of a mineralized structure, new crystals appear to bud from the imperfection, non-singular surface, step and faults, present on the host crystal surface. The new crystals grow usually in bivalve nacre by the spiral mechanism under stable secretion activity, but by the dendritic growth under unstable secretion activity. Consequently, the morphology and surface microtopographs of crystals are changed in each individual animal.
