Study of Spiral Growth Structure of Nacreous Layer from Pteria Penguin and Blister Pearl by AFM

The surface microtopography of the nacreous layer from Pteria Penguin and blister pearl (from Sanya, Hainan Province), including Pinctada Martensii, Hyriopsis Gumingi and freshwater cultured pearls, are observed by using atomic force microscope (AFM). The results show that the characteristics of size, quantity, orientation and the semidiameter of critical planar nucleus of spiral growth structure from the inner to the outer nacreous layer of the shells are obviously different, which could be related with the organic matrix.The growth structure of concentric cinularity also exits on the surface, which could be the steady state of spiral growth structure.The aragonite crystallite is of column for growing collectively and the height of each one is also different from nan-three-dimensional space image, proving aragonite crystallite being spiral piled along the crystallo-graphic orientation.According to the study before, on the basis of BCP theory and 3-D nucleation growth mechanism, a mode of the spiral growth structure is established tentatively.