Quartz crystal is a mineral made of silicon dioxide that has piezoelectric properties. In other words, the quartz will develop an electrical potential upon the application of a mechanical stress. Introducing an AC voltage across the electrodes of a crystal will generate an oscillation at a resonant frequency. The quartz crystal exhibits a high “quality factor”, or Q, that leads to a very stable oscillation and lends itself to be used as a very accurate timing device found in nearly all electronic products.