Electron contrast effects from oscillating quartz crystals seen by the scanning electron microscope

Some observations on the SEM patterns of the state of the surface of a few quartz crystals, both in non oscillating and oscillating states at low and high magnifications are presented and discussed. The electroded portion of a quartz crystal becomes darker as the oscillations are developed and their ampUtude is allowed to increase in steps. The unelectroded portion shows evidence of polarization charge distribution produced by oscillations. The distribution is complex, reflecting the complexity of ultrasonic oscillation modes of the quartz crystal.