Atomic clocks keep time by means of quartz crystals and periodic radio-controlled synchronization with the NIST atomic clock. Visitors to this website will find comparisons of radio-controlled clocks and watches.
A wall clock can serve as a stylish wall decoration in addition to telling time. Modern wall clocks use quartz movements run by battery power, while traditional wall clocks may rely on weights and pendulums.
Gold-encrusted quartz from 500 metres below the surface in an area three metres wide and three metres high has delivered rocks weighing up to 90 kilograms, worth millions, in just days.
Jarrod Lucas. Australian Broadcasting Corporation. Mon, 10 Sep 2018 08:10:19 +1000.