The nacre of mussel shell of Tellinella asperrima was analyzed with HRTEM. results show that the shape of aragonite platelets of the nacre in shell appears irregularly polygon. The thickness of organic matrix layers is rather uneven. There exist mineral bridges in organic matrix interface between two aragonite platelets. The size of the mineral bridge is uneven and it is distributed at random. Many disorderly distributed stacking faults exist within the aragonite tablets. According to XRD analysis, there is a strong preferential orientation of (002) plane in nacre, simultaneously (014) plane and (012) plane also present weak preferential orientations. In addition, the phase transformation was studied by DTA and TG. The result showed that the transition temperature of aragonite (360-380 degrees C) in the shell is lower than the natural aragonite (450-500 degrees C) under the influence of organic matrix. (c) 2008 Elsevier B.V. All rights reserved.