
Flint, occasionally flintstone, is a
sedimentary cryptocrystalline form of the
mineral quartz, categorized as the variety of
chert that occurs in
chalk or
marl
Marl is an earthy material rich in carbonate minerals, clays, and silt. When hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae.
Marl makes up the lower part o ...
y
limestone. Flint was widely used historically to make
stone tool
A stone tool is, in the most general sense, any tool made either partially or entirely out of stone. Although stone tool-dependent societies and cultures still exist today, most stone tools are associated with prehistoric (particularly Stone Ag ...
s and
start fires.
It occurs chiefly as
nodules and masses in sedimentary rocks, such as
chalks and
limestones.
[''The Flints from Portsdown Hill'']
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. 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 stream ...
s and
beaches.
Flint breaks and chips into sharp-edged pieces, making it useful for knife blades and other cutting tools. The use of flint to make
stone tools dates back hundreds of thousands of years, and 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 prehistoric period during which stone was widely used to make tools with an edge, a point, or a percussion surface. The period lasted for roughly 3.4 million years, and ended between 4,000 BC and 2,000 BC, with t ...
.
During the Stone Age, access to flint was so important for survival that people would travel or trade to obtain flint.
Flint Ridge Flint Ridge () is a north-south trending ridge with a summit elevation of in the Asgard Range of Victoria Land, Antarctica. On the west side of the ridge is Sagittate Hill, tall and mostly composed of exposed rock. At the south end of the ridge si ...
in
Ohio was an 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 and south around the
Gulf of Mexico.
When struck against steel, flint will produce enough sparks to ignite a fire with the correct
tinder, or
gunpowder used
in weapons, namely the
flintlock 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 trap, ...
. Although it has been superseded in these uses by different processes (the
percussion cap), or materials (
ferrocerium), "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. One
hypothesis is that a gelatinous material fills cavities in the sediment, such as holes bored by
crustaceans or
molluscs and that this becomes
silicified. 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 (Demospongiae) are the most diverse class in the phylum Porifera. They include 76.2% of all species of sponges with nearly 8,800 species worldwide (World Porifera Database). They are sponges with a soft body that covers a har ...
s).
[ Certain types of flint, such as that from the south coast of England and its counterpart on the French side of the ]Channel
Channel, channels, channeling, etc., may refer to:
Geography
* Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water.
Australia
* Channel Country, region of outback Austral ...
, 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. Thin slices of the stone often reveal this effect.
Flint sometimes occurs in large flint fields Flint fields (german: Feuersteinfelder) are large natural deposits of flint. They are found in numerous Jurassic and Cretaceous beds across the whole of Europe. in Jurassic or Cretaceous beds, for example, in Europe. Puzzling giant flint formations known as paramoudra
Paramoudras, paramoudra flints, pot stones or potstones are flint nodules found mainly in parts of north-west Europe: Norfolk (United Kingdom), Ireland, Denmark, Spain and Germany. In Norfolk they are known as pot stones and can be found on th ...
and flint circles are found around Europe but especially in Norfolk, England on the beaches at Beeston Bump
Beeston Regis is a village and civil parish in the North Norfolk district of Norfolk, England.Ordnance Survey (2002). ''OS Explorer Map 252 – Norfolk Coast East''. . It is about a mile (2 km) east of Sheringham, Norfolk and near the coast ...
and West Runton
West Runton is a village in North Norfolk, England, on the North Sea coast.
Toponymy
The villages name means either, Runa's farm/settlement' or 'Runi's farm/settlement'.
Overview
West Runton and East Runton together form the parish of 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 seas hundreds of millions of years ago that hardened into limestone and later became infused with silica. The flint from Flint Ridge is found in many hues like red, green, pink, blue, white and gray, with the color variations caused by minute impurities of iron compounds.
Flint can be coloured: sandy brown, medium to dark gray, 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 prehistoric period during which stone was widely used to make tools with an edge, a point, or a percussion surface. The period lasted for roughly 3.4 million years, and ended between 4,000 BC and 2,000 BC, with t ...
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 made of another material). This process is referred to as knapping.
Flint mining is attested since the Paleolithic
The Paleolithic or Palaeolithic (), also called the Old Stone Age (from Greek: παλαιός ''palaios'', "old" and λίθος ''lithos'', "stone"), is a period in human prehistory that is distinguished by the original development of stone too ...
, but became more common since the Neolithic (Michelsberg culture, Funnelbeaker culture). 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 Paris Basin, Thy in Jutland (flint mine at Hov), the Sennonian deposits of Rügen, Grimes Graves in England, the Upper Cretaceous chalk formation of Dobruja and the lower Danube (Balkan flint), the Cenomanian chalky marl formation of the Moldavian Plateau (Miorcani flint) and the Jurassic deposits of the Kraków area and Krzemionki in Poland, as well as of the Lägern ( silex) in the Jura Mountains
The Jura Mountains ( , , , ; french: Massif du Jura; german: Juragebirge; it, Massiccio del Giura, rm, Montagnas da Jura) are a sub-alpine mountain range a short distance north of the Western Alps and mainly demarcate a long part of the Frenc ...
of Switzerland.
In 1938, a project of the Ohio Historical Society, 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, Alonzo W. Pond Alonzo W. Pond (1894–25 December 1986) was an American archaeologist.
Born in Janesville, Wisconsin, he was assistant curator of the Logan Museum of Anthropology in Beloit, Wisconsin in 1924. Between 1925 and 1930 he conducted excavations of preh ...
, Francis H. S. Knowles and Don Crabtree.
To combat 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 from the atmosphere and can ignite the proper tinder.
Prior to the wide availability of steel, rocks of pyrite (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, used primarily in flintlock 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") 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 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 (sometimes referred to as "flint", although not true flint, " mischmetal", "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 fires when used correctly, ferrocerium is commonly included in survival kits. 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.
As a building material
Flint, knapped or unknapped, has been used from antiquity (for example at the Late Roman fort of Burgh Castle 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 in the East of England, often defined as including the counties of Norfolk, Suffolk and Cambridgeshire. The name derives from the Anglo-Saxon kingdom of the East Angles, a people whose name originated in Anglia, in ...
, but also used in chalky areas stretching through Hampshire, Sussex, Surrey
Surrey () is a ceremonial and non-metropolitan county in South East England, bordering Greater London to the south west. Surrey has a large rural area, and several significant urban areas which form part of the Greater London Built-up Area. ...
and Kent to Somerset.
Flint was used in the construction of many churches, houses, and other buildings, for example, the large stronghold of Framlingham Castle. Many different decorative effects have been achieved by using different types of knapping or arrangement and combinations with stone ( flushwork), 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 within the South Somerset administrative district.
The A30 road passes nearby. The parish has a population of 50. It is noted for the historic ...
, 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, Norfolk, showing alternating courses of flint and brick
A brick is a type of block used to build walls, pavements and other elements in masonry construction. Properly, the term ''brick'' denotes a block composed of dried clay, but is now also used informally to denote other chemically cured cons ...
File:Surroundings of Canterbury Cathedral 02.JPG, A typical medieval wall (with modern memorial) at Canterbury Cathedral
Canterbury Cathedral in Canterbury, Kent, is one of the oldest and most famous Christian structures in England. It forms part of a World Heritage Site. It is the cathedral of the Archbishop of Canterbury, currently Justin Welby, leader of the ...
– knapped and unknapped ("cobble") flints are mixed with pieces of brick and other stones
File:2004 thetford 03.JPG, Ruins of Thetford 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
A chromophore is the part of a molecule responsible for its color.
The color that is seen by our eyes is the one not absorbed by the reflecting object within a certain wavelength spectrum of visible light. The chromophore is a region in the molec ...
oxides and so are less deleterious to the colour of the ceramic composition after firing.
Until recently flint was also an important raw material in clay-based ceramic bodies produced in the UK. In preparation for use flint pebbles, frequently sourced from the coasts of South-East England or Western France, were calcined to around . This heating process both removed organic impurities and induced certain physical reactions, including converting some of the silica to cristobalite. After calcination the flint pebbles were milled to a fine particle size. However, the use of flint has now been superseded by quartz.[ 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 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
*
*
*
*
Archaeology
*
* , archaeological artefacts of the Clovis culture in New Mexico, USA
* , a prehistoric flint mine in Norfolk, 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
Firelighting
Firelighting using percussion
Building stone