Flint is a hard,
sedimentarySedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
cryptocrystallineCryptocrystalline is a rock texture made up of such minute crystals that its crystalline nature is only vaguely revealed even microscopically in thin section by transmitted polarized light. Among the sedimentary rocks, chert and flint are cryptocrystalline. Carbonado, a form of diamond, is also...
form of the
mineralA mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
quartzQuartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
, categorized as a variety of
chertChert is a fine-grained silica-rich microcrystalline, cryptocrystalline or microfibrous sedimentary rock that may contain small fossils. It varies greatly in color , but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements...
. It occurs chiefly as
noduleA nodule in petrology or mineralogy is a secondary structure, generally spherical or irregularly rounded in shape. Nodules are typically solid replacement bodies of chert or iron oxides formed during diagenesis of a sedimentary rock...
s and masses in sedimentary rocks, such as
chalkChalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores....
s and
limestoneLimestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
s. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and often has a glassy or waxy appearance. A thin layer on the outside of the nodules is usually different in colour, typically white and rough in texture. From a
petrologicalPetrology is the branch of geology that studies rocks, and the conditions in which rocks form....
point of view, "flint" refers specifically to the form of
chertChert is a fine-grained silica-rich microcrystalline, cryptocrystalline or microfibrous sedimentary rock that may contain small fossils. It varies greatly in color , but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements...
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
diagenesisIn geology and oceanography, diagenesis is any chemical, physical, or biological change undergone by a sediment after its initial deposition and during and after its lithification, exclusive of surface alteration and metamorphism. These changes happen at relatively low temperatures and pressures...
. One
hypothesisA hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...
is that a gelatinous material fills cavities in the sediment, such as holes bored by crustaceans or molluscs and that this becomes 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. Certain types of flint, such as that from the south coast of England, contain trapped fossilised marine flora. Pieces of coral and vegetation have been found preserved like
amberAmber is fossilized tree resin , which has been appreciated for its color and natural beauty since Neolithic times. Amber is used as an ingredient in perfumes, as a healing agent in folk medicine, and as jewelry. There are five classes of amber, defined on the basis of their chemical constituents...
inside the flint. Thin slices of the stone often reveal this effect.
Puzzling giant flint formations known as
paramoudraParamoudras, Paramoudra flints, Pot stones or Potstones are flint nodules found mainly in parts of north-west Europe: Norfolk , Ireland, Denmark, Basque Country and Germany. In Norfolk they are known as Pot Stones and can be found on the beach below Beeston Bump just outside of Beeston Regis...
and flint circles are found around Europe but especially in Norfolk, England on the beaches at Beeston Bump and
West RuntonWest Runton is a village in North Norfolk, England, approximately ¼ of a mile from the North Sea coast.-Overview:West Runton and East Runton together form the parish of Runton. The village straddles the A149 North Norfolk coast road and is 2½ miles west of Cromer and 1½ miles east of Sheringham...
.
Tools or cutting edges
Flint was used for the manufacture of flint tools during the
Stone AgeThe Stone Age is a broad prehistoric period, lasting about 2.5 million years , during which humans and their predecessor species in the genus Homo, as well as the earlier partly contemporary genera Australopithecus and Paranthropus, widely used exclusively stone as their hard material in the...
as it splits into thin, sharp splinters called flakes or blades (depending on the shape) when struck by another hard object (such as a
hammerstoneIn archaeology, a hammerstone is a hard cobble used to strike off lithic flakes from a lump of tool stone during the process of lithic reduction. The hammerstone is a rather universal stone tool which appeared early in most regions of the world including Europe, India and North America...
made of another material). This process is referred to as knapping.
In
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, some of the best toolmaking flint has come from
BelgiumBelgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
(Obourg, flint mines of
SpiennesSpiennes is a Walloon village in the municipality of Mons, Belgium.It is well known for its neolithic flint mines, which are on the list of UNESCO World Heritage Sites since 2000....
), the coastal chalks of the
English ChannelThe English Channel , often referred to simply as the Channel, is an arm of the Atlantic Ocean that separates southern England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest to in the Strait of Dover...
, the
Paris BasinThe Paris Basin is one of the major geological regions of France having developed since the Triassic on a basement formed by the Variscan orogeny.-Extent:...
,
ThyThy is a traditional district in northwestern Jutland, Denmark. It is situated north of the Limfjord, facing the North Sea and Skagerrak, and has a population of around 50,000. The main towns of Thy are Thisted, Hanstholm and Hurup....
in
JutlandJutland , historically also called Cimbria, is the name of the peninsula that juts out in Northern Europe toward the rest of Scandinavia, forming the mainland part of Denmark. It has the North Sea to its west, Kattegat and Skagerrak to its north, the Baltic Sea to its east, and the Danish–German...
(flint mine at Hov), the Sennonian deposits of
RügenRügen is Germany's largest island. Located in the Baltic Sea, it is part of the Vorpommern-Rügen district of Mecklenburg-Vorpommern.- Geography :Rügen is located off the north-eastern coast of Germany in the Baltic Sea...
,
Grimes GravesGrime's Graves is a large Neolithic flint mining complex near Brandon in England close to the border between Norfolk and Suffolk. It was worked between around circa 3000 BC and circa 1900 BC, although production may have continued well into the Bronze and Iron Ages owing to the low cost of flint...
in England and the
JurassicThe Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
deposits of the
KrakówKraków also Krakow, or Cracow , is the second largest and one of the oldest cities in Poland. Situated on the Vistula River in the Lesser Poland region, the city dates back to the 7th century. Kraków has traditionally been one of the leading centres of Polish academic, cultural, and artistic life...
area and
KrzemionkiKrzemionki, also Krzemionki Opatowskie - Neolithic and early Bronze Age complex of mines of the Upper Jurassic banded flints, located in the eastern Poland near Ostrowiec Świętokrzyski. It is the biggest complex of the prehistoric flint mines in Europe . .- History of mining :The mining area is...
in
PolandPoland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
. Flint mining is attested since the Palaeolithic, but became more common since the
NeolithicThe Neolithic Age, Era, or Period, or New Stone Age, was a period in the development of human technology, beginning about 9500 BC in some parts of the Middle East, and later in other parts of the world. It is traditionally considered as the last part of the Stone Age...
(Michelsberg culture,
Funnelbeaker cultureThe Funnelbeaker culture, short TRB from Trichterbecherkultur is the principal north central European megalithic culture of late Neolithic Europe.- Predecessor and successor cultures :...
).
To ignite fire or gunpowder
When struck against
steelSteel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
, a flint edge will produce sparks. The hard flint edge shaves off a particle of the steel that, heated by the friction, reacts with
oxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
from the atmosphere and can ignite the proper
tinderTinder is easily combustible material used to ignite fires by rudimentary methods. A small fire consisting of tinder is then used to ignite kindling. Anything that can be ignited by a match can be considered tinder; or by more rigorous definition, anything that begins to glow under a shower of...
. Prior to the wide availability of steel, rocks of iron pyrites would be used along with the flint, in a similar (but more time-consuming) way. These methods are popular in woodcraft, bushcraft, and among those who wish to use traditional skills.
Striking sparks with flint and steel is not a particularly easy or convenient method to start a
fireFire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....
, although it is much easier than some other primitive fire-making methods such as using a
bow drillThe bow drill is an ancient tool. While it was usually used to make fire, it was also used for primitive woodworking and dentistry. It consists of a bearing block or handhold, a spindle or drill, a hearth or fireboard, and a simple bow...
.
Fragmentation
While flints may be used in fire-lighting they should not be exposed to heating by fire. Stone fracturing can result from uneven molecule expansion, causing fragmentation when cohesion is exceeded.
To combat fragmentation, flint/chert may be heat-treated, being slowly brought up to a temperature of 150 to 260 °C (302 to 500 F) for 24 hours, then slowly cooled to room temperature. This makes the material more homogenous and thus more "knappable" and produces tools with a cleaner, sharper cutting edge.
Flintlocks
A later, major use of flint and steel was in the
Flintlock mechanismThe flintlock mechanism was a firing mechanism used on muskets and rifles in the 17th, 18th, and 19th centuries. It is commonly referred to as a "flintlock" , though that term is also commonly used for the weapons themselves as a whole, and not just the lock mechanism.The flintlock was developed in...
, used primarily in
flintlockFlintlock is the general term for any firearm based on the flintlock mechanism. The term may also apply to the mechanism itself. Introduced at the beginning of the 17th century, the flintlock rapidly replaced earlier firearm-ignition technologies, such as the doglock, matchlock and wheellock...
firearms, but also used on dedicated fire-starting tools. A piece of flint held in the jaws of a spring-loaded hammer, when released by a trigger, strikes a hinged piece of steel ("
frizzenThe frizzen, historically called the steel, is an "L" shaped piece of steel hinged at the rear used in flintlock firearms. It is positioned over the flash pan so as to enclose a small priming charge of black powder next to the flash hole that is drilled through the barrel into where the main...
") at an angle, creating a shower of sparks and exposing a charge of priming powder. The sparks ignite the priming powder and that flame, in turn, ignites the main charge, propelling the ball, bullet, or shot through the barrel. While the military use of the flintlock declined after the adoption of the
percussion capThe percussion cap, introduced around 1830, was the crucial invention that enabled muzzleloading firearms to fire reliably in any weather.Before this development, firearms used flintlock ignition systems which produced flint-on-steel sparks to ignite a pan of priming powder and thereby fire the...
from the 1840s onward, flintlock rifles and shotguns remain in use among hobbyists used in the United States.
Comparison with ferrocerium
Use of flint and steel should not be confused with use of
ferroceriumFerrocerium is a man-made metallic material that has the ability to give off a large number of hot sparks at temperatures at when scraped against a rough surface , such as ridged steel...
(aka "
mischmetalMischmetal is an alloy of rare earth elements in various naturally occurring proportions. It is also called cerium mischmetal, rare earth mischmetal or misch metal. A typical composition includes approximately 50% cerium and 25% lanthanum, with small amounts of neodymium and praseodymium...
", "hot spark", "metal match", or "fire steel"). This man-made material, when scraped with any hard, sharp edge, produces sparks that are much hotter than obtained with natural flint and steel, allowing use of a wider range of tinders. Because it can produce sparks when wet and can start hundreds or thousands of fires when used correctly, ferrocerium is a common item included in
survival kitA survival kit is a package of basic tools and supplies prepared in advance as an aid to survival in an emergency. Military aircraft, lifeboats, and spacecraft are equipped with survival kits....
s. Called "flint", ferrocerium is also used in many cigarette lighters.
As a building material
Flint, knapped or unknapped, has been used since antiquity (for example at the Late Roman fort of
Burgh CastleGariannonum, or Gariannum, was a Saxon Shore fort in Norfolk, England. The Notitia Dignitatum, a Roman Army “order of battle” from about AD 400, lists nine forts of the Saxon Shore in south and east England, among which one was called Gariannonor...
in
NorfolkNorfolk is a low-lying county in the East of England. It has borders with Lincolnshire to the west, Cambridgeshire to the west and southwest and Suffolk to the south. Its northern and eastern boundaries are the North Sea coast and to the north-west the county is bordered by The Wash. The county...
) up to the present day as a material for building stone walls, using lime mortar, and often combined with other available stone or brick rubble. It was most common in parts of southern England, where no good building stone was available locally, and
brickA brick is a block of ceramic material used in masonry construction, usually laid using various kinds of mortar. It has been regarded as one of the longest lasting and strongest building materials used throughout history.-History:...
-making not widespread until the later Middle Ages. It is especially associated with
East AngliaEast Anglia is a traditional name for a region of eastern England, named after an ancient Anglo-Saxon kingdom, the Kingdom of the East Angles. The Angles took their name from their homeland Angeln, in northern Germany. East Anglia initially consisted of Norfolk and Suffolk, but upon the marriage of...
, but also used in chalky areas stretching through
HampshireHampshire is a county on the southern coast of England in the United Kingdom. The county town of Hampshire is Winchester, a historic cathedral city that was once the capital of England. Hampshire is notable for housing the original birthplaces of the Royal Navy, British Army, and Royal Air Force...
,
SussexSussex , from the Old English Sūþsēaxe , is an historic county in South East England corresponding roughly in area to the ancient Kingdom of Sussex. It is bounded on the north by Surrey, east by Kent, south by the English Channel, and west by Hampshire, and is divided for local government into West...
,
SurreySurrey is a county in the South East of England and is one of the Home Counties. The county borders Greater London, Kent, East Sussex, West Sussex, Hampshire and Berkshire. The historic county town is Guildford. Surrey County Council sits at Kingston upon Thames, although this has been part of...
and
KentKent is a county in southeast England, and is one of the home counties. It borders East Sussex, Surrey and Greater London and has a defined boundary with Essex in the middle of the Thames Estuary. The ceremonial county boundaries of Kent include the shire county of Kent and the unitary borough of...
to
SomersetThe ceremonial and non-metropolitan county of Somerset in South West England borders Bristol and Gloucestershire to the north, Wiltshire to the east, Dorset to the south-east, and Devon to the south-west. It is partly bounded to the north and west by the Bristol Channel and the estuary of the...
. Flint was used in the construction of many churches, houses, and other buildings, for example the large stronghold of
Framlingham CastleFramlingham Castle is a castle in the market town of Framlingham in Suffolk in England. An early motte and bailey or ringwork Norman castle was built on the Framlingham site by 1148, but this was destroyed by Henry II of England in the aftermath of the revolt of 1173-4...
. Many different decorative effects have been achieved by using different types of knapping or arrangement and combinations with stone (
flushwork-Description:In architecture, flushwork is the decorative combination on the same flat plane of flint and ashlar stone. It is characteristic of the external walls of medieval buildings, most of the survivors being churches, in parts of Southern England, but especially East Anglia...
), especially in the 15th and early 16th centuries.
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 based on colour; those having a tint of red (indicates iron content) are discarded. The remaining blue-grey stones have a low content of chromophoric oxides and so impart lesser amounts of colouring contaminants.
In the UK, flint pebbles were traditionally an important raw material for clay-based
ceramicA ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
bodies. After
calcinationCalcination is a thermal treatment process applied to ores and other solid materials to bring about a thermal decomposition, phase transition, or removal of a volatile fraction. The calcination process normally takes place at temperatures below the melting point of the product materials...
to remove organic impurities and induce certain physical reactions, and milling to fine particle size, flint was added as a filler to
potteryPottery is the material from which the potteryware is made, of which major types include earthenware, stoneware and porcelain. The place where such wares are made is also called a pottery . Pottery also refers to the art or craft of the potter or the manufacture of pottery...
bodies. However, flint is no longer used and has been replaced by quartz as is used in other countries. Because of this historical use, the word "flint" is used by US potters to refer to siliceous materials which are not flint.
See also
- Mineralogy
- Agate
Agate is a microcrystalline variety of silica, chiefly chalcedony, characterised by its fineness of grain and brightness of color. Although agates may be found in various kinds of rock, they are classically associated with volcanic rocks and can be common in certain metamorphic rocks.-Etymology...
- Chalcedony
Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of the minerals quartz and moganite. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monoclinic...
- Chert
Chert is a fine-grained silica-rich microcrystalline, cryptocrystalline or microfibrous sedimentary rock that may contain small fossils. It varies greatly in color , but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements...
- Eolith
An eolith is a chipped flint nodule. Eoliths were once thought to have been artifacts, the earliest stone tools, but are now believed to be naturally produced by geological processes such as glaciation....
- Jasper
Jasper, a form of chalcedony, is an opaque, impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. This mineral breaks with a smooth surface, and is used for ornamentation or as a gemstone. It can be highly polished and is used for vases, seals, and at one time for...
- Nodule (geology)
A nodule in petrology or mineralogy is a secondary structure, generally spherical or irregularly rounded in shape. Nodules are typically solid replacement bodies of chert or iron oxides formed during diagenesis of a sedimentary rock...
not to be confused with ConcretionA concretion is a volume of sedimentary rock in which a mineral cement fills the porosity . Concretions are often ovoid or spherical in shape, although irregular shapes also occur. The word 'concretion' is derived from the Latin con meaning 'together' and crescere meaning 'to grow'...
- Obsidian
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock.It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth...
- Onyx
Onyx is a banded variety of chalcedony. The colors of its bands range from white to almost every color . Commonly, specimens of onyx contain bands of black and/or white.-Etymology:...
- Opal
Opal is an amorphous form of silica related to quartz, a mineraloid form, not a mineral. 3% to 21% of the total weight is water, but the content is usually between 6% to 10%. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most...
- Whinstone
Whinstone is a term used in the quarrying industry to describe any hard dark-coloured rock. Examples include the igneous rocks basalt and dolerite as well as the sedimentary rock chert....
- Archaeology
- Clovis Point
Clovis points are the characteristically-fluted projectile points associated with the North American Clovis culture. They date to the Paleoindian period around 13,500 years ago. Clovis fluted points are named after the city of Clovis, New Mexico, where examples were first found in 1929.At the right...
s, archaeological artefacts of the Clovis cultureThe Clovis culture is a prehistoric Paleo-Indian culture that first appears 11,500 RCYBP , at the end of the last glacial period, characterized by the manufacture of "Clovis points" and distinctive bone and ivory tools...
in New MexicoNew Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
- Grimes Graves
Grime's Graves is a large Neolithic flint mining complex near Brandon in England close to the border between Norfolk and Suffolk. It was worked between around circa 3000 BC and circa 1900 BC, although production may have continued well into the Bronze and Iron Ages owing to the low cost of flint...
, a prehistoric flint mine in NorfolkNorfolk is a low-lying county in the East of England. It has borders with Lincolnshire to the west, Cambridgeshire to the west and southwest and Suffolk to the south. Its northern and eastern boundaries are the North Sea coast and to the north-west the county is bordered by The Wash. The county...
, England
External links