Tools or cutting edges flint axe, about 31 cm long spearpoint about long Flint was used in the manufacture of tools during the
Stone Age, 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, but became more common since the
Neolithic (notably among the
Michelsberg culture and
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 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,
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. If temperatures exceed this, the flint has a tendency to explode; therefore deliberate use of this technique suggests a strong understanding of pyrotechnology. The current earliest evidence of deliberately heat-treated chert comes from
Hoedjiespunt 1 in South Africa, dating
MIS- 5e (130-119 kya) which corresponds to the
Middle Stone Age.
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 s typical of
Roman to
Medieval period 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 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 kits. Ferrocerium is used in many
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 the parts of southern England where no good building stone was available locally, and where brick-making was not widespread until the
late Middle Ages. It is especially associated with
East Anglia, but also used in chalky areas stretching through
Hampshire, Sussex,
Surrey 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, 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 File:Surroundings of Canterbury Cathedral 02.JPG|A typical medieval wall (with modern memorial) at
Canterbury Cathedral – 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 oxides and so are less
deleterious to the colour of the ceramic composition after
firing. flint Until recently
calcined flint was also an important raw material in clay-based
ceramic 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. However, the use of flint has now been superseded by
quartz.
Jewelry Flint bracelets were known in
Ancient Egypt, and several examples have been found. ==See also==