Abstract
Chiton tooth cusps are known to be one of the biominerals forming the amorphous precursor phases, though the biomineralization process and mechanism are not really understood. In order to promote further understanding of the biomineralization process, the immature to mature tooth cusps in two chiton species, Acantopleura japonica and Acantochitona achates, were investigated by various analytical techniques, micro-XRD, synchrotron-XRD, micro-XANES, and FIB-TEM.