Gastropod nacre

For continuation of mineral growth in the vertical direction, a CP has to be secreted and for reasons of conformation a phase shift is introduced. This may account for the brick-wall pattern in pelecypod or the zig-zag-pattern in stacks of gastropod nacre. Structures of this type resemble clay minerals, which are also capable of incorporating structural water between metal ion polyhedra. 

H. Nakahara, Calcification in Gastropod Nacre, in Biomineralization and Biological Metal Acciunulation , eds. P. Westbroek and E. W. de Jong, Reidel Pubhshing Company, Dordrecht, 1983, p. 225. 

Wise, S. W. Microarchitecture and mode of formation of nacre (mother of pearl) in pelece-pods, gastropods and cephalopods. Eclogae geol. Helv. 63, 775 (1976)... 

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