What does quartz mean in a clock?
The stability of a semiconductor oscillator is not good enough for a clock. A quartz crystal is used as a component in an oscillator to provide a stable resonator to establish the frequency. For example, for a clock to be stable to within 1 minute per month, the oscillator must be stable to one part in 43000 in spite of temperature variation.
Because quartz will last much longer than a semi conductor. Also, a quartz crystal will naturally oscillate and a semi conductor has to have an outside influence.
