The molluscan shell is a natural ceramic composite with excellent fracture strength and fracture toughness, which are attributed to their unique microstructures. SEM observation on Bivalva shell showed that the shell consists of laminated aragonites and organic layers. There are different shapes and arrangements of aragonites. The higher fracture roughness of this laminated microstructure is analyzed. The laminated microstructure of the shell is used for the biomimetic designs of the ceramic/polymer and ceramic/polymer/fiber composite. Comparison of test of the biomimetic ceramic composite with the original ceramic material shows that the fracture toughness of the biomimetically designed ceramic composite increases markedly than that of the original ceramic material. (C) 2004 Elsevier Ltd and Techna Group S.r.l. All rights reserved.