A crystal that vibrates on cue
Quartz is a crystal of silicon dioxide with an unusual property: squeeze it and it produces a small electric voltage, and apply a voltage and it changes shape slightly. This is called the piezoelectric effect, and the brothers Pierre and Jacques Curie demonstrated it in 1880. For decades it was a laboratory curiosity.
The link to timekeeping comes from what happens when a carefully cut piece of quartz is placed in an electronic circuit. The crystal vibrates at a very stable frequency set mostly by its size and shape, and the circuit uses the crystal to keep its own oscillations on track. A pendulum or a balance wheel is a mechanical swinging object; the crystal does the same job with far less movement and at a much higher frequency.
From radio to clocks
The first uses of quartz oscillators were in radio, where they helped transmitters stay on their assigned frequency. In 1927, Warren Marrison and colleagues at Bell Telephone Laboratories built the first quartz clock. It was a large piece of laboratory apparatus, not a household item. Over the next decades, quartz clocks became standard in observatories and standards laboratories, where they proved steadier than the best pendulum clocks. They stayed in the laboratory for a while because they needed bulky vacuum-tube electronics, which were far too large for a wrist.
Shrinking the clock
Making a quartz watch required two further technologies: a tiny crystal and a way to count its vibrations in a very small space. The crystal part was solved by cutting it into a tuning-fork shape that vibrates at a low frequency. The most common frequency is 32,768 hertz, which is 2 to the power 15. A chain of fifteen divide-by-two stages brings 32,768 cycles per second down to exactly one pulse per second, which can then drive a display or a small motor. That is why the number appears in so many watches.
The counting was made possible by integrated circuits, which could pack the dividing stages and control logic into a chip small enough to fit in a case. Low-power chips were important, because a watch battery has to last a year or more.
The first quartz watches
Several groups worked on the problem in the 1960s, including research labs in Switzerland and Japan. A Swiss prototype from the Center Electronique Horloger, known as the Beta 21, appeared in 1970, and a Japanese company released the Seiko Astron on December 25, 1969, widely cited as the first quartz wristwatch sold to the public. It was expensive, with a price that many accounts describe as very high for a watch of the time.
An earlier electronic watch, the Accutron from the US in 1960, used a vibrating tuning fork instead of a crystal and helped prove that people would buy a watch without a conventional balance wheel.
In 1972, a US company introduced the first digital watch with a red light emitting diodes display. The display was only lit when you pressed a button, because of battery drain. Soon liquid crystal displays replaced it, because they used far less power and allowed a display that was always on.
Prices fall quickly
As with other electronics, the cost of the components dropped fast. Large semiconductor companies entered the market with cheap digital watches, and prices fell during the 1970s from the level of luxury goods to the level of ordinary consumer items. A watch that kept time to within a minute a month became affordable for almost everyone, which was a larger change than any one clever design. Typical quartz watches commonly keep time within a few seconds to a few tens of seconds per month; temperature and age affect the rate.
Inside analog quartz watches, the same crystal drives a tiny stepping motor, a miniature relative of the electric motors in appliances, which advances the hands in small jumps. Later models added solar panels to charge the battery, and some used the kinetic energy of the wearer’s arm.
The shock to mechanical watchmaking
The impact on the traditional industry, especially in Switzerland, is often called the quartz crisis. Mechanical watches rely on skilled labor and many fine parts, while a quartz movement has far fewer. As cheap quartz watches spread in the 1970s and early 1980s, many established watchmakers lost market share, and a large number of workers and firms in the Swiss industry disappeared. The exact figures vary between sources, but the decline was severe.
The recovery came in part from a different strategy. Low-cost, colorful plastic watches built around simple quartz movements showed that Swiss firms could compete in volume, and at the other end, mechanical watches were repositioned as crafted objects. Today few people buy a mechanical watch because it keeps better time than a quartz watch; most buy it for the craftsmanship, the design or the tradition.
Beyond the wristwatch
The same oscillator shaped everything with a digital clock inside. Quartz crystals keep time in computers, clocks, radios and many appliances, usually without anyone noticing. In the mid-2010s the idea of the watch shifted again with the arrival of smartwatch design that adds sensors and wireless connections to a watch case. Even then, a small crystal is typically still counting seconds inside, with the exact time often set by phone or network.
Why quartz mattered
Quartz was a turning point because it separated accuracy from craft. Before, a good watch was the product of precision machining and careful regulation. After, accuracy came from a mass-produced crystal and a chip, so the best timekeeping was available to everyone at low cost. It also set the pattern for later consumer electronics: a component born in a laboratory, miniaturized, and sold in huge numbers.