The α-quartz trigonal symmetry revealed by fracture tests
Reuschlé, Thierry; Darot, Michel
European Journal of Mineralogy Volume 8 Number 4 (1996), p. 695 - 702
published: Jul 29, 1996
manuscript accepted: Mar 28, 1996
manuscript received: Sep 6, 1995
ArtNo. ESP147050804005, Price: 29.00 €
Abstract Subcritical crack growth experiments on quartz single crystals have been carried out. Reproducibility of the results was checked by running tests on several samples in the same crack propagation direction. The results show the prominent role that water plays in controlling the crack velocity. Crack propagation tests run in two opposite directions show striking differences which confirm previous results. These differences are mainly due to the anisotropy of the quartz surface energy. Microstructural observations of the fracture surfaces for two opposite crack propagation directions give evidence for this anisotropy which is the consequence of the α-quartz trigonal symmetry. Our results confirm the subtle difference in the adjacent m directions, as already shown by electron channelling patterns.