The Microstructure of Biogenic Calcite: A View by High-Resolution Synchrotron Powder Diffraction


  • This work was partially supported by the Israel Science Foundation founded by the Israel Academy of Science and Humanities. B. P. would like to acknowledge financial help from the ESRF in support of this work in the framework of the program for visiting scientists. The help of Dr. M. Brunelli in collecting the X-ray diffraction data at ESRF is also gratefully acknowledged. We thank Prof. Steve Weiner (Weizmann Institute of Science, Rehovot, Israel) for supplying the specimens of Atrina rigida shells and Dr. Frederic Marin (UMR, CNRS, Dijon, France) for supplying the specimens of Pinna nobilis shells.


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Biogenic calcite obtained from different mollusk shells is subjected to heat treatments at elevated temperatures and structurally analyzed by high-resolution synchrotron X-ray powder diffraction. Remarkable broadening of diffraction peaks in samples annealed at temperatures above 200 °C is observed (see figure), indicating heat-induced degradation of intra-crystalline proteins occluded in the mineral lattice during biomineralization.