Flint
43701
224829620
2008-07-10T16:34:57Z
217.44.222.172
Useage
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[[Image:Flint.jpg|thumb|A flint nodule from the [[Onondaga (geological formation)|Onondaga]] limestone layer, [[Buffalo, New York]]. (3.8 cm wide)]]
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[[Image:flintbeach.jpg|thumb|upright|Pebble beach made up of flint nodules eroded out of the nearby [[chalk]] cliffs, [[Cape Arkona]], [[Rügen]]]]
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[[Image:Feuersteinaxt.jpg|thumb|Late [[Stone Age]] flint axe, about 31 cm long]]
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[[Image:Flint Wall Wiltshire.JPG|thumb|Detail of flint used in a building in Wiltshire, England.]]
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{{otheruses1|the sedimentary rock}}
'''Flint''' (or '''flintstone''') is a hard, [[sedimentary rock|sedimentary]] [[cryptocrystalline]] form of the [[mineral]] [[quartz]],<ref>[http://webmineral.com/data/Quartz.shtml General Quartz Information] - Webmineral.com (page contains [[java applet]]s depicting 3d molecular structure)</ref><ref>[http://www.quartzpage.de/flint.html Flint and Chert] - quartzpage.de</ref> categorized as a variety of [[chert]]. Flint is usually dark grey, black, green, white, or deep brown in colour, and often has a waxy appearance. It occurs chiefly as [[Nodule (geology)|nodule]]s and masses in sedimentary rocks, such as [[chalk]]s and [[limestone]]s.<ref name=Flints>http://www.bbm.me.uk/portsdown/PH_320_Flint.htm ''The Flints from Portsdown Hill''</ref><ref>http://www.theaaca.com/Learning_Center/flintvs.htm Flint vs Chert Authentic Artefacts Collectors Assn.</ref> From a [[petrology|petrological]] point of view, "flint" refers specifically to the form of [[chert]] which occurs in chalk or marly limestone. Similarly, "common chert" (sometimes referred to simply as "chert") occurs in limestone.
The exact mode of formation of flint is not yet clear but it is thought that it occurs as a result of chemical changes in compressed sedimentary rock formations, during the process of [[diagenesis]]. One [[hypothesis]] is that a gelatinous material fills cavities in the sediment, such as holes bored by [[crustaceans]] or [[molluscs]] and that this becomes [[silicification|silicified]]. This theory certainly explains the complex shapes of flint nodules that are found. The source of dissolved silica in the porous media could arise from the spicules of silicious sponges.<ref name=Flints/>
== Uses ==
===Tools===
Flint was used for the manufacture of [[flint tool]]s during the [[Stone Age]], as it splits into thin, sharp splinters called flakes or blades (depending in the shape) when struck by another hard object (such as a [[hammerstone]] made of another material). This process is referred to as [[knapping]].
In [[Europe]], some of the best toolmaking flint has come from [[Belgium]] (Obourg, flint mines of [[Spiennes]]<ref>http://www.minesdespiennes.org/en.html Neolithic Flint Mines of Petit-Spiennes ''Official web site''</ref>), the coastal chalks of the [[English Channel]], the [[Paris Basin (geology)|Paris Basin]], [[Thy (district)|Thy]] in [[Jutland]] (flint mine at Hov), the Sennonian deposits of [[Rügen]], [[Grimes Graves]] in England and the [[Jurassic]] deposits of the [[Kraków]] area in [[Poland]]. Flint mining is attested since the [[Palaeolithic]], but became more common since the [[Neolithic]] (Michelsberg culture, [[Funnelbeaker culture]]).
===Fire===
When struck against [[steel]], flint will produce [[spark|sparks]], which when directed onto [[tinder]] can be used to start a [[fire]]. This occurs when the hard flint knocks off a particle of the steel, which is heated by the impact, and then burns with oxygen from the atmosphere. This method is popular in [[woodcraft]] and among [[camping|campers]] who want to have an 'authentic' experience. Striking a lump of flint against a piece of steel to make fire is not particularly easy or convenient (although it is much easier than other primitive fire-making methods such as using a [[fire stick|bow and drill]]). Because of this, a [[Ferrocerium|similar technology]] has been miniaturized and integrated into [[Cigarette lighter|lighters]], which are easy to use without skill or practice. The [[ferrocerium]] used in these lighters, while sometimes called "flint", works differently from true flint-and-steel, with the steel scraping off slivers of burning ferrocerium, the reverse of traditional flint-and- steel.<ref>http://www.wildwoodsurvival.com/survival/fire/flintandsteel/RBclarifications.html Flint and steel clarifications</ref> Starting a fire with flint, however, is a staple of [[scouting]] lore.
A later major use was to create the spark that would ignite the powder that would fire a ball or bullet from a [[flintlock]] firearm. While the military use of a flintlock declined after the [[British military]] generally applied the [[percussion cap]] on their [[muskets]] in [[1842]], it is still popular to use the flintlock as a hunting rifle during special [[muzzleloader]] [[hunting season|seasons]] or general [[rifle]] seasons in several states in the [[United States|US]].
===Building===
Flint was used from the [[13th century]] until the present day as a material for building stone walls, especially in parts of the [[United Kingdom of Great Britain and Northern Ireland|UK]]. In chalky areas, mostly coastal, but also including inland areas such as the [[North Downs|North]] and [[South Downs]] in southern England, flint has also been used as a building and walling material, predating the common use of bricks but laid in a similar manner, using lime mortar. For instance, flint was used in the construction of many churches and other buildings in [[East Anglia]], [[Kent]], [[Sussex]] and [[Surrey]].
[[Image:flint church in england arp.jpg|thumb|left|upright|A flint [[church]] - the Parish Church of Saint Thomas, in [[Cricket Saint Thomas]], [[Somerset]], [[England]]. The “bricks” width varies between 3 and 5 inches (8-13 cm).]]
===Ceramics===
Flint pebbles are used as the media in ball mills to grind glazes and other raw materials for the ceramics industry. The pebbles are hand-selected for colour, with those showing a reddish tint, indicating the presence of [[iron]], being discarded. The remaining blue-grey stones have a low content of [[chromophoric]] oxides and so should impart lesser amounts of colouring contaminants.
In the UK, flint pebbles were traditionally used to yield an important raw material for clay-based [[ceramic]] bodies. After high temperature treatment ([[calcination]]) to remove organic impurites and induce certain physical reactions, and milling to fine particle size, flint was added as a filler to [[pottery]] bodies, performing a similar role to the quartz sand used in other countries. Because of this historical use, the word "flint" is now erroneously used by American, and some British potters, to siliceous materials used in some clay bodies and glazes.<ref>''Dictionary of Ceramics''. 3rd edition. Dodd A. The Institute of Materials. 1994; Hamer, F. and Hamer, J., ''The Potter's Dictionary of Materials and Techniques'', London, A & C Black, 2004, ISBN 0-8122-3810-9, p.144</ref>
==See also==
{{Commons|Flintstone}}
*[[Chert]]
*[[Eolith]]
*[[Obsidian]]
*[[Grimes Graves]], a prehistoric flint mine in [[Norfolk]], [[England]]
==External links==
* [http://www.flintsource.net/ Flintsource.net European Artefacts - detailed site]
* [http://www.czech.cz/en/news/science-and-discovery/oldest-mines-in-europe-uncovered-in-south-moravia Flint mine in South Moravia 9,400 yrs old]
==References==
<references/>
{{Silica minerals}}
[[Category:Sedimentary rocks]]
[[Category:Lithics]]
[[Category:Quartz varieties]]
[[Category:Firelighting]]
[[Category:Symbols of Ohio]]
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