Why is Quartz used in Watches?
Quartz crystals are used in the mechanisms of watches because when bent or compressed, the crystals produce a charge or voltage on their surface. This is called the Piezoelectric effect and it produces just the right amount of power needed to drive the mechanisms of a watch. Interestingly, the relationship works both ways -if you apply a charge to a quartz crystal it will bend or change shape very slightly.
Straight bars or discs or quartz are perfect for keeping time because small bars can oscillate at a low frequency of 32KHz. The accuracy of the time-keeping depends on the precision with which the tiny bar or tuning fork of quartz is cut.
The mechanisms of the watch make the crystal ring. The ringing crystal shakes (or oscillates) at a nice regular rhythm (like a pendulum but at thousands of times per second) and gives off a tiny electronic signals (because of the piezoelectric effect) which are then converted into the pulses needed for keeping time.
