# Why Quartz



## jasonm (Nov 22, 2003)

I know Quartz has a known occilation which is how it is used for timekeeping, but why hasnt anyone tried other minerals, Rubys etc? I know cost would be a factor but it would be a interesting selling point......Or am I talking out of my arse?


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## pg tips (May 16, 2003)

jasonm said:


> Or am I talking out of my arse?
> 
> 
> 
> ...


more than likely


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## rhaythorne (Jan 12, 2004)

> but why hasnt anyone tried other minerals


I presume they have and quartz is the only viable solution? Or maybe I'm talking out of my arse as well







A coal-powered watch would be interesting


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## jasonm (Nov 22, 2003)

Cheers Paul!


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## JoT (Aug 12, 2003)

Jason I can only think of tourmaline as the only other significantly piezoelectric mineral, although there are loads that are slightly piezoelectric. Thing with quartz the frequency depends on the size of the crystal, I also think most crystals are now synthetic to avoid impurities.

Quartz has been used since the early 1920's (crystal radios). I suppose its was only the advent of micro-electronics that allowed the development of quartz watches even though the principle was established decades ago.


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## jasonm (Nov 22, 2003)

Thanks John.


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## Roy (Feb 23, 2003)

I think everything else has/was tried and quartz was the most stable.


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## Silver Hawk (Dec 2, 2003)

They should have stopped with tuning forks....









Mind you, the living room, bedroom, office, kitchen, car would all be much noisier places if they had


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## mach 0.0013137 (Jan 10, 2005)

I thought this might be of interest taken from "Timepieces, masterpieces of chronometry" by David Christianson ;-

"In 1928 Warren A. Marrison (1896-1980) of Bell Telephone Laboratories in New York developed the first quartz crystal clock."

Christianson goes on to say "By the end of World War II quartz clocks could sustain an accuracy of about 1 seconds variance in 30 years"

Its amazing how old the "new" technology really is


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## Roger (May 17, 2003)

Jase,

Quartz is commonly used because it is cheap...there are a few other materials that will oscillate when excited by a small electric current....I think Rhubidiam and Caesium are a couple ( stand to be corrected on this)... but quartz is cheap and available.

When excited by a small current, the crystal will oscillate at a frequency determined by the shape and manner in which it is cut.

The usual and most common frequency is 32,768 Hz or cycles /sec.

The tiny integrated ciruit will consist of lots of " divide-by-two" circuits ( keep dividing 32768 by 2 and you will get down to 1Hz or 1 cycle per second.....in an analogue watch this drives a stepper motor once per second to give the familiar stepping on the second hand.

In a digital it drives display circuity of either LEDs ( nice) or LCD (almost as nice but more practical)

I have a Seiko perpetual calendar whose quartz frequency is 196,608 Hz, which gives greater accuracy.

Hope this helps

Roger


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## jasonm (Nov 22, 2003)

Thanks for your replys guys...


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## JoT (Aug 12, 2003)

Rubidium and Ceasium are alkali metal elements and not minerals. They are both rather unpleasant and very reactive with both air and water. Ceasium is also liquid at room temperature.

Caesium however is used in atomic clocks and its constant resonating frequency of over 9 billion per second is now a standard measure of time.

I don't think they are piezoelectric like quartz, I think they resonate without applied pressure/electricty


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## JoT (Aug 12, 2003)

Just read up on ceasium clocks .... I dont think its a wrist watch option







The create a Caesium vapour in an oven, bombard it with microwaves in an vacum! What's really interesting is that quartz is responsible for keeping the time not the caesium









"_The part of an atomic clock which is responsible for keeping time is actually a quartz crystal oscillator. In most quartz clocks, the oscillator is tuned accurately when the clock is made but its frequency is never checked again. Over time, its frequency changes slightly but unpredictably, making the clock fast or slow._

The purpose of the complicated apparatus in an atomic clock is to check the frequency of the quartz oscillator continually, giving the clock its great accuracy.

An atom can be thought of as a collection of electrons orbiting a nucleus like planets around the Sun. Calculations using quantum mechanics show that only certain orbits are allowed. To move from a high orbit to a lower one, an electron must emit energy in the form of electromagnetic radiation (light or radio waves) of a particular frequency. This frequency depends on the energy difference between the two orbits. If an electron in the lower orbit is supplied with radiation of exactly the right frequency, it will jump to the higher orbit.

Each caesium atom contains 55 electrons. The last of these normally occupies an orbit which is much further from the nucleus than the rest. In this orbit, its energy can have two slightly different values, depending on a property called the "spin" of the electron. The energy difference between the two states corresponds to radio waves with a frequency of 9192631770 Hz (cycles per second). Atoms in these two states have slightly different magnetic properties.

At one end of the caesium clock is an oven which evaporates atoms of caesium from the surface of a piece of the metal. These atoms will have their electrons in one of the two arrangements described above. A magnet is used to separate them and discard those with the higher energy.

The clock's quartz crystal oscillator is tuned as accurately as possible to 9192631770 Hz. It controls a source of radio waves aimed at the atoms with the lower energy. If the crystal's frequency is correct, many of the atoms have their states changed.

The atoms in the changed state are counted by a detector. If the number which have been changed starts to fall, it is because the frequency of the quartz crystal has drifted. In that case, an automatic control system adjusts the crystal oscillator until the number of atoms being changed reaches a maximum again. Preventing the crystal's frequency from changing keeps the clock accurate. An electronic counter converts the oscillation frequency to pulses at intervals of exactly one second.

The principle was first suggested by Dr. Isador Rabi of Columbia University in the 1930s.


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## Roger (May 17, 2003)

> I think they resonate without applied pressure/electricty


John, this is a little deep for my, but I think all materials have a natural resonant frequency, but is that really the same thing as oscillation???

I tend to look at things in electronic terms, but are the two things the sam???

Roger


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## JoT (Aug 12, 2003)

Roger this is trying my physics to it limit









Piezoelectric minerals respond to pressure and or alternating current, the best analogy is a bell,the frequency quartz osciliates depends on the size and shape of the crystal.

The caesium ... its all to do with raising electrons to a higher energy level (using the feindish sounding microwave contraption) ; as the electrons fall back to a lower energy level they emit a high frequency radio wave of 9,192,631,770 Hz! It is this frequency that the quartz crystal in the atomic clock is tuned to.


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## Griff (Feb 23, 2003)

A read up on quartz for interest


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## jasonm (Nov 22, 2003)

I enjoyed that Griff, thanks....









2 years to the day after my original post


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## pg tips (May 16, 2003)

He's a thread resurrector!

Loved this



> 13. Why are nearly all women's watches quartz-powered?
> 
> Watch companies have found that women are less interested in the mechanics of a watch than in its styling. Since quartz movements are less expensive, more accurate and don't need winding, women tend to prefer them. That's why Patek Philippe, for example, uses quartz movements in nearly all of its women's watches but mechanical ones in most of its men's watches.
> 
> Furthermore, companies have found that women who want the cachet of a mechanical watch prefer men's models because they're larger and often easier to identify by brand than women's watches. The Swiss company Breitling, for example, sells many men's watches to fashionable, status-conscious women.


They could just as easily have put because most women are lazy bitches and a mechanical would soon stop working!


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## Boxbrownie (Aug 11, 2005)

pg tips said:


> He's a thread resurrector!
> 
> Loved this
> 
> ...


Oooooooo.......duck you fool....DUCK!


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## Boxbrownie (Aug 11, 2005)

Too late......she got him


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