Editing Clock (section)

===Quartz===

[[File:Inside QuartzCrystal-Tuningfork.jpg|thumb|Picture of a quartz crystal resonator, used as the timekeeping component in quartz watches and clocks, with the case removed. It is formed in the shape of a tuning fork. Most such quartz clock crystals vibrate at a frequency of {{val|32768|u=Hz}}.]]

The [[piezoelectric]] properties of crystalline [[quartz]] were discovered by [[Jacques Curie|Jacques]] and [[Pierre Curie]] in 1880.<ref name=nistrevolution>{{cite web|url= http://physics.nist.gov/GenInt/Time/revol.html |title= A Revolution in Timekeeping |access-date= 30 April 2008 |publisher= NIST| archive-url = https://web.archive.org/web/20080409174853/http://physics.nist.gov/GenInt/Time/revol.html | archive-date = April 9, 2008}}</ref><ref>{{cite web |url=http://www.aip.org/history/curie/pierre.htm |title=Pierre Curie |access-date=8 April 2008 |publisher=[[American Institute of Physics]] |archive-date=February 16, 2015 |archive-url=https://web.archive.org/web/20150216035509/http://www.aip.org/history/curie/pierre.htm  }}</ref> The first crystal oscillator was invented in 1917 by [[Alexander M. Nicholson]], after which the first quartz crystal oscillator was built by [[Walter Guyton Cady|Walter G. Cady]] in 1921.<ref name=Marrison /> In 1927 the first [[quartz clock]] was built by Warren Marrison and J.W. Horton at [[Bell Telephone Laboratories]] in Canada.<ref name="Marrison2">{{Cite journal|last=Marrison|first=W.A.|author2=Horton, J.W. |title=Precision determination of frequency|journal=I.R.E. Proc.|volume=16|pages=137–154|date=February 1928|doi=10.1109/JRPROC.1928.221372|issue=2|s2cid=51664900}}</ref><ref name="Marrison" /> The following decades saw the development of quartz clocks as precision time measurement devices in laboratory settings—the bulky and delicate counting electronics, built with [[vacuum tube]]s at the time, limited their practical use elsewhere. The National Bureau of Standards (now [[NIST]]) based the time standard of the United States on quartz clocks from late 1929 until the 1960s, when it changed to atomic clocks.<ref name="Sullivan">{{cite web|last=Sullivan|first=D.B.|year=2001|title=Time and frequency measurement at NIST: The first 100&nbsp;years|publisher=Time and Frequency Division, National Institute of Standards and Technology|url=http://tf.nist.gov/timefreq/general/pdf/1485.pdf|page=5|archive-url=https://web.archive.org/web/20110927062444/http://tf.nist.gov/timefreq/general/pdf/1485.pdf|archive-date=September 27, 2011}}</ref> In 1969, [[Seiko]] produced the world's first quartz [[Watch|wristwatch]], the [[Astron (wristwatch)|Astron]].<ref>{{cite web | publisher = IEEE History Center | title = Electronic Quartz Wristwatch, 1969 | url = http://ethw.org/Milestones:Electronic_Quartz_Wristwatch,_1969 | access-date = 11 July 2015 | archive-date = January 22, 2016 | archive-url = https://web.archive.org/web/20160122104239/http://ethw.org/Milestones:Electronic_Quartz_Wristwatch,_1969 | url-status = live }}</ref> Their inherent accuracy and low cost of production resulted in the subsequent proliferation of quartz clocks and watches.<ref name=nistrevolution />