First evidence of synthetic polygonal serpentines
Devouard, Bertrand; Baronnet, Alain; Van Tendeloo, Gustaaf; Amelinckx, Severin
European Journal of Mineralogy Volume 9 Number 3 (1997), p. 539 - 546
published: Jun 2, 1997
manuscript accepted: Jan 14, 1997
manuscript received: Dec 19, 1995
ArtNo. ESP147050903005, Price: 29.00 €
Abstract Hydrothermal syntheses on the stoichiometric composition 3MgO-2SiO2 plus excess H2O can reproduce the various rolled structures of natural serpentines. However, synthetic polygonal serpentine has not been reported yet, probably due to difficulties in TEM sample preparation. We describe herein an embedding preparation technique followed by ion milling, which allows HRTEM axial imaging of synthetic serpentine fibres. Selected-area electron diffraction (SAED) patterns of single fibres could also be recorded. Like their natural counterparts synthetic fibres with a diameter greater than 100 nm unambiguously display polygonal arrangements of 15- and 30-sector types, and various stacking sequences including regular multi-layer polytypes. These results suggest that the origin of polygonization is probably controlled by temperature and/or growth (kinetic) parameters.