The effects of physically loading the surface of two types of piezoelectric quartz oscillator plates have been experimentally investigated. Various amounts of Wood's metal were applied to different parts of the crystal surfaces. Thickness-shear-mode plates were benefited only when the metal was applied on or near the active central area of the plate, but X-cut crystals employing an extensional mode of vibration responded favorably only when the metal was applied near the periphery of the plate. In both types of oscillator plates loading increased the crystal unit Q several fold. Activity-frequency characteristics over a temperature range —60° to +90°C were greatly improved.