Pressure-induced amorphization of wollastonite (CaSiO3) at room temperature

Abstract

Energy dispersive x-ray diffraction and Raman measurements show that the mineral wollastonite (CaSiO3) becomes amorphous at a pressure of 25.6 GPa at 300 K. A consideration of the high pressure/high temperature behavior of CaSiO3 shows that the amorphization occurs because the phase transition wollastonite→perovskite CaSiO3 is kinetically impeded. We suggest that the amorphous phase may be viewed as a defective long-period modulated wollastonite phase.