In vitro growth of nacre-like tablet forming: From amorphous calcium carbonate, nanostacks to hexagonal tablets

The Structure and formation mechanism of nacre are hot research topics in biomineralization. However, there is no specific conclusion about them. Especially for individual nacre tablet forming, many hypotheses still exist. Here we report an in vitro crystal growth on a nacre Surface, by which we monitored in real time the growth process of nacre-like tablets and layers on the fresh nacre surface. The formation of nacre-like tablets was a complex and multistep process, from an amorphous calcium carbonate (ACC) layer, iso-oriented nanostacks to hexagonal tablets. We suggest that the interlamellar organic matrix of nacre absorbed calcium and carbonate in amorphous form, and the ACC layer acted as a temporary storage for aragonite crystals. Aragonite nanostacks grew Lip easily by two-dimensional crystal growth, and then assembled into hexagonal tablets. This process is fascinating, and the proposed mechanisms of nacre-like tablets forming may have indirect and relevant implications for real nacre tablets forming.