Flint

Flint (or flintstone) is a hard, limestones.^[1][2]

The exact mode of formation of flint is not yet clear or agreed 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 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.^[1]

Uses

Tools

Flint was used for the manufacture of flint tools 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^[3]), 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 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 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.^[4] 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 seasons or general rifle seasons in several states in the US.

Building

Flint was used extensively from the 13th century until the present day as a material for building stone walls, especially in parts of the UK. In chalky areas, mostly coastal, but also including inland areas such as the 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.

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 chromophoric oxides and so should impart lesser amounts of colouring contaminants.

In the UK, flint pebbles were traditionally an important raw material for clay-based calcined flint performed a similar role to the quartz sand used in other countries, i.e. after milling to fine particle size was the filler component in pottery bodies. Because of this historical use, the term flint is now used by American potters for all siliceous fillers.

See also

• Eolith
• Obsidian
• Grimes Graves, a prehistoric flint mine in Norfolk, England

References

1. ^ ^{a b} http://www.bbm.me.uk/portsdown/PH_320_Flint.htm The Flints from Portsdown Hill
2. ^ http://www.theaaca.com/Learning_Center/flintvs.htm Flint vs Chert Authentic Artefacts Collectors Assn.
3. ^ http://www.minesdespiennes.org/en.html Neolithic Flint Mines of Petit-Spiennes Official web site
4. ^ http://www.wildwoodsurvival.com/survival/fire/flintandsteel/RBclarifications.html Flint and steel clarifications