HIGH-RESOLUTION TRANSMISSION ELECTRON-MICROSCOPY OF PRESSURE-AMORPHIZED ALPHA-QUARTZ

Alpha-quartz becomes x-ray amorphous when compressed, at ambient temperature, by pressures of 25 to 30 GPa [Hemley et al., Nature 334, 5 (1988)]. The relationship between pressure-amorphized and melt-quenched silica is of great interest. The most fundamental characteristic of melt-quenched silica is its lack of periodicity at the atomic level. We report here that high-resolution electron microscopy shows that alpha-quartz, pressure amorphized at 30.5 GPa is, as is conventional melt-quenched silica, amorphous at the atomic level.