What is quartz, and how does it work in watch and electronic circuits? How does it helps in watch and electronic circuit broad?
Is there any material to refer?
 A: I don't have any notes you can refer to but quartz is a piezo-electric substance. What that means is that when any physical stress is applied to it, it produces a small amount of current and also vice versa. For example, if I send a small current towards a quartz crystal, it will oscillate. The converse is also true, where if I oscillate the crystal, it will produce a minute amount of current. In watches and electronic circuits, the battery supplies a small amount of current to the quartz crystal, which makes it oscillate at a very precise frequency, exactly 32768 Hz. This is used to keep time as this frequency allows the clock to tick at just the right time.
A: Quartz is silicon dioxide (SiO2); the crystal form called 'alpha-quartz'
is a hexagonal crystal (which you have probably seen, because it is a
common and rather attractive mineral).   In that crystal form, the
application of stress will slightly polarize the material (cause electric
charge to move), and the inverse effect also holds (electric charge applied
to the crystal will cause it to change shape).
The final piece of the puzzle, is that quartz is acoustically 'live', i.e.
it rings like a bell.  Like a bell, the acoustic pitch depends on shape
and size, so it can be shaped and sized for a
wide range of different frequencies of oscillation.
A sculpted piece of crystal can be used in an oscillating electric circuit to selectively
generate an accurate frequency.   Tuning of radios was an early application, and many others followed.  Networked data,  like radio, requires accurate timing at multiple locations.  Clocks, too, benefit from the mass-production of time standards in quartz crystal form.
