Application of synchrotron radiation to the study of high-pressure zeolite phases. Case of scolecite
Pressure-induced amorphization has already been observed in some framework silicates like quartz and feldspars. A similar crystal to highly disordered solid transition is reported in this study fora zeolite named scolecite, which is the calcium end-member of the natrolite group. Pressure-induced amorphization is demonstrated using in-situ X-ray diffraction and Raman spectroscopy. This transformation is preceded by polymorphic transitions and occurs below 10 GPa. The crystal-amorphous transition is irreversible and the pressure quenched samples exhibit Raman spectra which bear strong resemblance with alumino-silicate glasses obtained by quenching a liquid. In some cases however, decompression is accompanied by a rim recrystallisation of the sample. The role of shear stresses seems thus to be crucial during the decompression of the samples.