Natural fresh scallop and nacre were used in the present work.Chemical composition

structure characteristics and thermal analysis were investigated in details.Scallop and nacre were both consisted of ~95% CaCO3 and ~5% organic matrix.The inorganic phase of scallops was almost 100% calcite

and the inorganic phase of mother of pearl shells was consisting of 4.96% calcite and 95.04% aragonite.And organic matrix separated from scallop and nacre was different.The result of thermal analysis indicated that thermal analysis included degeneration and decomposition of organic matter and decomposition of calcium carbonate two stages.The difference is that polymorph conversion from aragonite into calcite in nacre at 400-500℃.It provides basic data for the biomineralization.