Flint, occasionally flintstone, is a
sedimentary
Sedimentary rocks are types of rock formed by the cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedime ...
cryptocrystalline
Cryptocrystalline is a rock microstructure, 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 a ...
form of the
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...
quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...
, categorized as the variety of
chert
Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...
that occurs in
chalk
Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Ch ...
or
marl
Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae.
M ...
y
limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
. Historically, flint was widely used to make
stone tool
Stone tools have been used throughout human history but are most closely associated with prehistoric cultures and in particular those of the Stone Age. Stone tools may be made of either ground stone or knapped stone, the latter fashioned by a ...
s and
start fires.
Flint occurs chiefly as
nodule
Nodule may refer to:
* Nodule (geology), a small rock or mineral cluster
* Manganese nodule, a metallic concretion found on the seafloor
*Nodule (medicine), a small aggregation of cells
*Root nodule
Root nodules are found on the roots of plants, ...
s and masses in sedimentary rocks, such as
chalk
Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Ch ...
s and
limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
s.
[''The Flints from Portsdown Hill''](_blank)
Inside the nodule, flint is usually dark grey or black, green, white, or brown in colour, and has a glassy or waxy appearance. A thin, oxidised layer on the outside of the nodules is usually different in colour, typically white and rough in texture. The nodules can often be found along
stream
A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a strea ...
s and
beach
A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from Rock (geology), rock, such as sand, gravel, shingle beach, shingle, pebbles, etc., or biological s ...
es.
Flint breaks and chips into sharp-edged pieces, making it useful in constructing a variety of cutting tools, such as knife blades and scrapers. The use of flint to make
stone tools
Stone tools have been used throughout human history but are most closely associated with prehistoric cultures and in particular those of the Stone Age. Stone tools may be made of either ground stone or knapped stone, the latter fashioned by a c ...
dates back more than three million years; flint's extreme durability has made it possible to accurately date its use over this time. Flint is one of the primary materials used to define the
Stone Age
The Stone Age was a broad prehistory, prehistoric period during which Rock (geology), stone was widely used to make stone tools with an edge, a point, or a percussion surface. The period lasted for roughly 3.4 million years and ended b ...
.
During the Stone Age, access to flint was so important for survival that people would travel or trade long distances to obtain the stone.
Grime's Graves
Grime's Graves is a large Neolithic flint mining complex in Norfolk, England. It lies north east from Brandon, Suffolk in the East of England. It was worked between 2600 and 2300 BCE, although production may have continued throug ...
was an important source of flint traded across Europe.
Flint Ridge in
Ohio
Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...
was another important source of flint, and
Native Americans extracted the flint from hundreds of quarries along the ridge. This "Ohio Flint" was traded across the eastern United States, and has been found as far west as the
Rocky Mountains
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of Western Can ...
and south around the
Gulf of Mexico
The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...
.
When struck against steel, flint will produce enough sparks to ignite a fire with the correct
tinder
Tinder is easily Combustibility and flammability, combustible material used to Firemaking, start a fire. Tinder is a finely divided, open material which will begin to glow under a shower of sparks. Air is gently wafted over the glowing tinder unt ...
, or
gunpowder
Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, charcoal (which is mostly carbon), and potassium nitrate, potassium ni ...
used
in weapons, namely the
flintlock
Flintlock is a general term for any firearm that uses a flint-striking lock (firearm), ignition mechanism, the first of which appeared in Western Europe in the early 16th century. The term may also apply to a particular form of the mechanism its ...
firing mechanism
A trigger is a mechanism that actuates the function of a ranged weapon such as a firearm, airgun, crossbow, or speargun. The word may also be used to describe a switch that initiates the operation of other non-shooting devices such as a tra ...
. Although it has been superseded in these uses by different processes (the
percussion cap
The percussion cap, percussion primer, or caplock, introduced in the early 1820s, is a type of single-use percussion ignition device for muzzle loader firearm locks enabling them to fire reliably in any weather condition. Its invention gave ...
), or materials (
ferrocerium
Ferrocerium (also known in Europe as Auermetall) is a synthetic pyrophoric alloy of mischmetal (cerium, lanthanum, neodymium, other trace lanthanides and some iron – about 95% lanthanides and 5% iron) hardened by blending in oxides ...
), "flint" has lent its name as generic term for a fire starter.
Origin

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
Diagenesis () is the process of physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition. Increased pressure and temperature only start to play a role as sedi ...
. One
hypothesis
A hypothesis (: hypotheses) is a proposed explanation for a phenomenon. A scientific hypothesis must be based on observations and make a testable and reproducible prediction about reality, in a process beginning with an educated guess o ...
is that a gelatinous material fills cavities in the sediment, such as holes bored by
crustaceans
Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of Arthropod, arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquat ...
or
molluscs
Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...
and that this becomes
silicified
In geology, silicification is a process in which silica-rich fluids seep into the voids of Earth materials, e.g., rocks, wood, bones, shells, and replace the original materials with silica (SiO2). Silica is a naturally existing and abundant com ...
. This hypothesis would certainly explain the complex shapes of flint nodules that are found. The source of dissolved silica in the porous media could be the
spicules of silicious sponges (
demosponge
Demosponges or common sponges are sponges of the class Demospongiae (from + ), the most diverse group in the phylum Porifera which include greater than 90% of all extant sponges with nearly 8,800 species
A species () is often de ...
s).
[ Certain types of flint, such as that from the south coast of England and its counterpart on the French side of the Channel, contain trapped fossilised marine flora. Pieces of coral and vegetation have been found preserved inside the flint similar to insects and plant parts within ]amber
Amber is fossilized tree resin. Examples of it have been appreciated for its color and natural beauty since the Neolithic times, and worked as a gemstone since antiquity."Amber" (2004). In Maxine N. Lurie and Marc Mappen (eds.) ''Encyclopedia ...
. Thin slices of the stone often reveal this effect.
Flint sometimes occurs in large flint fields in Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...
or Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...
beds, for example, in Europe. Puzzling giant flint formations known as paramoudra and flint circles are found around Europe but especially in Norfolk, England, on the beaches at Beeston Bump and West Runton.
The "Ohio flint" is the official gemstone of Ohio state. It is formed from limey debris that was deposited at the bottom of inland Paleozoic
The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...
seas hundreds of millions of years ago that hardened into limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
and later became infused with silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant f ...
. The flint from Flint Ridge is found in many hues like red, green, pink, blue, white, and grey, with the colour variations caused by minute impurities of iron compounds.
Flint can be coloured: sandy brown, medium to dark grey, black, reddish brown or an off-white grey.
Uses
Tools or cutting edges
Flint was used in the manufacture of tools during the Stone Age
The Stone Age was a broad prehistory, prehistoric period during which Rock (geology), stone was widely used to make stone tools with an edge, a point, or a percussion surface. The period lasted for roughly 3.4 million years and ended b ...
as it splits into thin, sharp splinters called flakes or blades (depending on the shape) when struck by another hard object (such as a hammerstone
In 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 wo ...
made of another material). This process is referred to as knapping
Knapping is the shaping of flint, chert, obsidian, or other conchoidal fracturing stone through the process of lithic reduction to manufacture stone tools, strikers for flintlock firearms, or to produce flat-faced stones for building or facing w ...
.
Flint mining is attested since the Paleolithic
The Paleolithic or Palaeolithic ( years ago) ( ), also called the Old Stone Age (), is a period in human prehistory that is distinguished by the original development of stone tools, and which represents almost the entire period of human prehist ...
, but became more common since the Neolithic
The Neolithic or New Stone Age (from Ancient Greek, Greek 'new' and 'stone') is an archaeological period, the final division of the Stone Age in Mesopotamia, Asia, Europe and Africa (c. 10,000 BCE to c. 2,000 BCE). It saw the Neolithic Revo ...
(Michelsberg culture, Funnelbeaker culture
The Funnel(-neck-)beaker culture, in short TRB or TBK (, ; ; ), was an archaeological culture in north-central Europe.
It developed as a technological merger of local neolithic and mesolithic techno-complexes between the lower Elbe and middle V ...
). In Europe, some of the best toolmaking flint has come from Belgium (Obourg, flint mines of Spiennes), the coastal chalks of the English Channel
The English Channel, also known as the Channel, is an arm of the Atlantic Ocean that separates Southern England from northern France. It links to the southern part of the North Sea by the Strait of Dover at its northeastern end. It is the busi ...
, the Paris Basin
The Paris Basin () is one of the major geological regions of France. It developed since the Triassic over remnant uplands of the Variscan orogeny (Hercynian orogeny). The sedimentary basin, no longer a single drainage basin, is a large sag in ...
, Thy in Jutland
Jutland (; , ''Jyske Halvø'' or ''Cimbriske Halvø''; , ''Kimbrische Halbinsel'' or ''Jütische Halbinsel'') is a peninsula of Northern Europe that forms the continental portion of Denmark and part of northern Germany (Schleswig-Holstein). It ...
(flint mine at Hov), the Sennonian deposits of Rügen
Rügen (; Rani: ''Rȯjana'', ''Rāna''; , ) is Germany's largest island. It is located off the Pomeranian coast in the Baltic Sea and belongs to the state of Mecklenburg-Western Pomerania.
The "gateway" to Rügen island is the Hanseatic ci ...
, Grimes Graves
Grime's Graves is a large Neolithic flint mining complex in Norfolk, England. It lies north east from Brandon, Suffolk in the East of England. It was worked between 2600 and 2300 BCE, although production may have continued throug ...
in England, the Upper Cretaceous chalk formation of Dobruja
Dobruja or Dobrudja (; or ''Dobrudža''; , or ; ; Dobrujan Tatar: ''Tomrîğa''; Ukrainian language, Ukrainian and ) is a Geography, geographical and historical region in Southeastern Europe that has been divided since the 19th century betw ...
and the lower Danube
The Danube ( ; see also #Names and etymology, other names) is the List of rivers of Europe#Longest rivers, second-longest river in Europe, after the Volga in Russia. It flows through Central and Southeastern Europe, from the Black Forest sou ...
(Balkan flint), the Cenomanian chalky marl formation of the Moldavian Plateau
The Moldavian Plateau () is a geographic area of the historical region of Moldavia, spanning nowadays the east and northeast of Romania, most of Moldova (except the south), and most of the Chernivtsi Oblast of Ukraine (where it is known as the ''P ...
(Miorcani flint) and the Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...
deposits of the Kraków
, officially the Royal Capital City of Kraków, is the List of cities and towns in Poland, second-largest and one of the oldest cities in Poland. Situated on the Vistula River in Lesser Poland Voivodeship, the city has a population of 804,237 ...
area and Krzemionki
Krzemionki, also Krzemionki Opatowskie (, " Opatów silica-mine"), is a Neolithic and early Bronze Age complex of flint mines for the extraction of Upper Jurassic ( Oxfordian) banded flints located about eight kilometers north-east of the Polish ...
in Poland, as well as of the Lägern (silex
Separation of isotopes by laser excitation (SILEX) is a process for enriching uranium to fuel nuclear reactors that may also present a growing nuclear weapons proliferation risk. It is strongly suspected that SILEX utilizes laser condensation repre ...
) in the Jura Mountains
The Jura Mountains ( ) are a sub-alpine mountain range a short distance north of the Western Alps and mainly demarcate a long part of the French–Swiss border. While the Jura range proper (" folded Jura", ) is located in France and Switzerla ...
of Switzerland.
In 1938, a project of the Ohio Historical Society
Ohio History Connection, formerly The Ohio State Archaeological and Historical Society and Ohio Historical Society, is a nonprofit organization incorporated in 1885. Headquartered at the Ohio History Center in Columbus, Ohio, Ohio History Connect ...
, under the leadership of H. Holmes Ellis began to study the knapping methods and techniques of Native Americans. Like past studies, this work involved experimenting with actual knapping techniques by creation of stone tools through the use of techniques like direct freehand percussion, freehand pressure and pressure using a rest. Other scholars who have conducted similar experiments and studies include William Henry Holmes
William Henry Holmes (December 1, 1846 – April 20, 1933), known as W. H. Holmes, was an American explorer, anthropologist, archaeologist, artist, scientific illustrator, cartographer, mountain climber, geologist and museum curator and dire ...
, Alonzo W. Pond, Francis H. S. Knowles and Don Crabtree.
To reduce susceptibility to fragmentation, flint/chert may be heat-treated, being slowly brought up to a temperature of for 24 hours, then slowly cooled to room temperature. This makes the material more homogeneous and thus more knappable and produces tools with a cleaner, sharper cutting edge. Heat treating was known to Stone Age artisans.
To ignite fire or gunpowder
When struck against steel, a flint edge produces sparks. The hard flint edge shaves off a particle of the steel that exposes iron, which reacts with oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
from the atmosphere and can ignite the proper tinder
Tinder is easily Combustibility and flammability, combustible material used to Firemaking, start a fire. Tinder is a finely divided, open material which will begin to glow under a shower of sparks. Air is gently wafted over the glowing tinder unt ...
.
Prior to the wide availability of steel, rocks of pyrite
The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Pyrite's metallic luster and pale brass-yellow hue ...
(FeS2) would be used along with the flint, in a similar (but more time-consuming) way. These methods remain popular in woodcraft, bushcraft, and amongst people practising traditional fire-starting skills.
Flintlocks
A later, major use of flint and steel was in the flintlock mechanism
The flintlock mechanism is a type of lock (firearm), lock used on muskets, rifles, and pistols from the early 17th to the mid-19th century. It is commonly referred to as a "flintlock" (without the word ''mechanism''). The term is also used for th ...
, used primarily in flintlock
Flintlock is a general term for any firearm that uses a flint-striking lock (firearm), ignition mechanism, the first of which appeared in Western Europe in the early 16th century. The term may also apply to a particular form of the mechanism its ...
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 ("frizzen
The frizzen, historically called the "hammer" or the steel,This may appear anomalous since, in later firearm designs (e.g. percussion locks), the component operating in the same manner as the ''cock'' is called the hammer. is an L-shaped piece of ...
") 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 cap
The percussion cap, percussion primer, or caplock, introduced in the early 1820s, is a type of single-use percussion ignition device for muzzle loader firearm locks enabling them to fire reliably in any weather condition. Its invention gave ...
from the 1840s onward, flintlock rifles and shotguns remain in use amongst recreational shooters.
Comparison with ferrocerium
Flint and steel used to strike sparks were superseded in the 20th century by ferrocerium
Ferrocerium (also known in Europe as Auermetall) is a synthetic pyrophoric alloy of mischmetal (cerium, lanthanum, neodymium, other trace lanthanides and some iron – about 95% lanthanides and 5% iron) hardened by blending in oxides ...
(sometimes referred to as "flint", although not true flint, "mischmetal
Mischmetal (from – "mixed metal") is an alloy of rare-earth elements. It is also called cerium mischmetal, or rare-earth mischmetal. A typical composition includes approximately 55% cerium, 25% lanthanum, and 15~18% neodymium ...
", "hot spark", "metal match", or "fire steel"). This human-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 fires when used correctly, ferrocerium is commonly included in survival kit
A survival kit is a package of basic tools and supplies prepared as an aid to survival skills, survival in an emergency. Civil and military aircraft, lifeboat (shipboard), lifeboats, and spacecraft are equipped with survival kits.
Survival ki ...
s. Ferrocerium is used in many cigarette lighters, where it is referred to as "a flint".
Fragmentation
Flint's utility as a fire starter is hampered by its property of uneven expansion under heating, causing it to fracture, sometimes violently, during heating. This tendency is enhanced by the impurities found in most samples of flint that may expand to a greater or lesser degree than the surrounding stone, and is similar to the tendency of glass to shatter when exposed to heat, and can become a drawback when flint is used as a building material
Building material is material used for construction. Many naturally occurring substances, such as clay, rocks, sand, wood, and even twigs and leaves, have been used to construct buildings and other structures, like bridges. Apart from natur ...
.
As a building material
Flint, knapped or unknapped, has been used from antiquity (for example at the Late Roman fort of Burgh Castle
Burgh Castle is a village and civil parish in the English county of Norfolk.
Burgh Castle is located south-west of Great Yarmouth and east of Norwich. The parish was part of Suffolk until 1974.
History
Burgh Castle was likely the site of a ...
in Norfolk) 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 those parts of southern England where no good building stone was available locally, and where brick-making was not widespread until the later Middle Ages. It is especially associated with East Anglia
East Anglia is an area of the East of England, often defined as including the counties of Norfolk, Suffolk and Cambridgeshire, with parts of Essex sometimes also included.
The name derives from the Anglo-Saxon kingdom of the East Angles, ...
, but also used in chalky areas stretching through Hampshire
Hampshire (, ; abbreviated to Hants.) is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Berkshire to the north, Surrey and West Sussex to the east, the Isle of Wight across the Solent to the south, ...
, Sussex, Surrey
Surrey () is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Greater London to the northeast, Kent to the east, East Sussex, East and West Sussex to the south, and Hampshire and Berkshire to the wes ...
and Kent
Kent is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Essex across the Thames Estuary to the north, the Strait of Dover to the south-east, East Sussex to the south-west, Surrey to the west, and Gr ...
to Somerset
Somerset ( , ), Archaism, archaically Somersetshire ( , , ) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by the Bristol Channel, Gloucestershire, and Bristol to the north, Wiltshire to the east ...
.
Flint was used in the construction of many churches, houses, and other buildings, for example, the large stronghold of Framlingham Castle
Framlingham Castle is a castle in the market town of Framlingham, Suffolk, England. An early motte and bailey or ringwork Norman castle was built on the Framlingham site by 1148, but this was destroyed (Slighting, slighted) by Henry II of Engl ...
. Many different decorative effects have been achieved by using different types of knapping or arrangement and combinations with stone (flushwork
In architecture, flushwork is decorative masonry work which combines on the same flat plane flint and ashlar stone. If the stone projects from a flat flint wall then the term is proudwork, as the stone stands "proud" rather than being "flush" w ...
), especially in the 15th and early 16th centuries. Because knapping flints to a relatively flush surface and size is a highly skilled process with a high level of wastage, flint finishes typically indicate high status buildings.
During World War I, in the chalky-soil country of France, the British filled sandbags with flint and used these sandbags as breastworks.
File:flint church in england arp.jpg, A flint church – the Parish Church of Saint Thomas, in Cricket Saint Thomas
Cricket St Thomas is a parish in Somerset, England, situated in a valley between Chard and Crewkerne and was formerly within the South Somerset administrative district.
The A30 road passes nearby. The parish has a population of 50. It is noted ...
, Somerset, England. The height of the very neatly knapped flints varies between .
File:Gariannonum Burgh Castle south wall well preserved close up.jpg, Close-up of the wall of the Roman shore fort at Burgh Castle
Burgh Castle is a village and civil parish in the English county of Norfolk.
Burgh Castle is located south-west of Great Yarmouth and east of Norwich. The parish was part of Suffolk until 1974.
History
Burgh Castle was likely the site of a ...
, Norfolk, showing alternating courses of flint and brick
A brick is a type of construction material used to build walls, pavements and other elements in masonry construction. Properly, the term ''brick'' denotes a unit primarily composed of clay. But is now also used informally to denote building un ...
File:Surroundings of Canterbury Cathedral 02.JPG, A typical medieval wall (with modern memorial) at Canterbury Cathedral
Canterbury Cathedral is the cathedral of the archbishop of Canterbury, the spiritual leader of the Church of England and symbolic leader of the worldwide Anglican Communion. Located in Canterbury, Kent, it is one of the oldest Christianity, Ch ...
– knapped and unknapped ("cobble") flints are mixed with pieces of brick and other stones.
File:2004 thetford 03.JPG, Ruins of Thetford
Thetford is a market town and civil parishes in England, civil parish in the Breckland District of Norfolk, England. It is on the A11 road (England), A11 road between Norwich and London, just east of Thetford Forest. The civil parish, coverin ...
Priory show flints and mortar through the whole depth of the wall
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, indicating high iron content, are discarded. The remaining blue-grey stones have a low content of chromophoric oxides and so are less deleterious to the colour of the ceramic composition after firing.
Until recently calcined
Calcination is thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O2 fraction of air), generally fo ...
flint was also an important raw material in clay-based ceramic
A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcela ...
bodies produced in the UK. In clay bodies, calcined flint attenuates the shrinkage whilst drying, and modifies the fired thermal expansion. Flint can also be used in glazes as a network former.['Ceramics Glaze Technology.' Taylor J.R. & Bull A.C. The Institute Of Ceramics & Pergamon Press. 1986.] In preparation for use flint pebbles, frequently sourced from the coasts of South-East England or Western France, were calcined
Calcination is thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O2 fraction of air), generally fo ...
to around . This heating process both removed organic impurities and induced certain physical reactions, including converting some of the quartz to cristobalite
Cristobalite ( ) is a mineral polymorph of silica that is formed at very high temperatures. It has the same chemical formula as quartz, Si O2, but a distinct crystal structure. Both quartz and cristobalite are polymorphs with all the members o ...
. After calcination the flint pebbles were crushed and milled to a fine particle size. However, the use of flint has now been superseded by quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...
.[ Because of the historical use of flint, the word "flint" is used by some potters (especially in the U.S.) to refer generically to siliceous raw materials used in ceramics that are not flint.]
Jewelry
Flint bracelets were known in Ancient Egypt, and several examples have been found.
See also
Mineralogy
*
*
*
*
*
* not to be confused with concretion
A concretion is a hard and compact mass formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular shapes a ...
*
*
*
*
Archaeology
*
* , archaeological artefacts of the Clovis culture
The Clovis culture is an archaeological culture from the Paleoindian period of North America, spanning around 13,050 to 12,750 years Before Present (BP). The type site is Blackwater Draw locality No. 1 near Clovis, New Mexico, where stone too ...
in New Mexico
New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...
, US
* , a prehistoric flint mine in Norfolk
Norfolk ( ) is a Ceremonial counties of England, ceremonial county in England, located in East Anglia and officially part of the East of England region. It borders Lincolnshire and The Wash to the north-west, the North Sea to the north and eas ...
, England
* , a Native American flint quarry in Hopewell Township, Licking County, Ohio, US
*
References
External links
Flint Architecture of East Anglia
Book by Stephen Hart
Flintsource.net European Artefacts – detailed site
Paramoudras and flint circles photograph collection
Introduction to the historical use of flint in construction and the repair and conservation of historic flint buildings
{{Authority control
Sedimentary rocks
Chert
Lithics
Fire making
Building stone