Reversed crystal growth of calcite in naturally occurring travertine crust
Abstract
A microstructural investigation by electron microscopy on a travertine specimen collected from Munigou National Park, Sichuan Province, China revealed evidence of a non-classical reversed crystal growth route previously only discovered in synthetic materials. Examination of the travertine specimen suggests that the presence of organic matter initiates the oriented aggregation of calcite nanocrystallites. Surface re-crystallisation of the aggregates leads to a single crystalline rhombohedral shell with a polycrystalline core. This core-shell structure carries a strong resemblance to synthetic calcite prepared in the presence of chitosan, where the growth of calcite was found to follow the so-called reversed crystal growth process. It is proposed that the similar roles of biomolecules in naturally occurring travertine and chitosan in the synthetic system are based on their isoelectric points and the polymerizable property of long chain chemical structures. This study is important so that the structural similarities between naturally occurring biominerals and biomimetic materials can be further understood.
Citation
Greer , H F , Zhou , W & Guo , L 2017 , ' Reversed crystal growth of calcite in naturally occurring travertine crust ' , Crystals , vol. 7 , no. 2 , 36 . https://doi.org/10.3390/cryst7020036
Publication
Crystals
Status
Peer reviewed
ISSN
2073-4352Type
Journal article
Rights
© 2017 by the authors; licensee MDPI, Basel, Switzerland. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
Description
WZZ thanks EPSRC for 510 financial support on FEG-SEM equipment (EP/F019580/1) and a Platform (EP/K015540/1).Collections
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