Published online by Cambridge University Press: 21 February 2011
The paper presents the detailed study of the structural features of the biomineralized bivalvia shells. The Cristaria plicata(Leach), Anodonta woodianal(Lea) and Lamprotula Leai(Gray) are selected as the prototype in the present study. Scanning electron microscope (SEM), X-ray diffraction, laser Raman spectroscope and electron spectroscopy for chemical analysis (ESCA) are employed to study the structures of the shells. It is found that three different layers of the shells possess distinct morphologies and structures with a clear boundary between every two layers. The prismatic layer can be further divided into two sub–layers. The preferential growth orientation of the biominerahzed phases were different from the natural ones. The Raman spectra present the detailed vibrational states of these biomineralized phases, while ESCA reveals that the chemical environments of the atoms in pearl layer are less varied than those in the other two layers.