Pure aragonite with novel urchin-like micropatterns was successfully prepared via a facile surfactant-assisted approach at 80 degreesC. The as-obtained products were determined by XRD, SEM, and TEM. The results reveal that the reaction temperature and the surfactant play important roles in determining the structure and morphology of the sample. This simple route might open opportunity to synthesize other carbonate with complex morphologies. (C) 2004 Elsevier B.V. All rights reserved.