Kelm, Klemens; Goetz, Andreas J.; Sehrbrock, Angelika; Irsen, Stephan; Hoffmann, Ramona; Schmahl, Wolfgang W.; Griesshaber, Erika
Mosaic structure in the spines of Holopneustes porossisimus.
In: Zeitschrift fur Kristallographie, Vol. 227, No. 11: pp. 758-765
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Sea urchin spines of Holopneustes porossisimus are porous singlecrystals, with the pores being filled with a material rich in carbon,silicon, fluorine and sodium. The magnesian calcite constituting thespine is highly strained. Even though the spines appear to be singlecrystalline on a macroscopic scale, the calcitic material exhibits anextended defect network. We find dislocations as well as rotational andother, not yet identified boundaries. We also observe within spinecalcite a patterned distribution of sulphur. Both distributions, that ofthe defect network and that of sulphur resemble in their pattern to eachother and have a similar mesh size of 50 nm. We conclude from theseobservations that they arise from the growth process of the spine andaccount for the mosaicity within the spine single crystals.