Stone tool
Stone has been used to make a wide variety of tools throughout history, including arrowheads, spearheads, hand axes, and querns.
[1] Knapped stone tools are made from cryptocrystalline materials such as chert, flint, radiolarite, chalcedony, obsidian, basalt, and quartzite via a splitting process known as lithic reduction.
One simple form of reduction is to strike stone flakes from a nucleus (core) of material using a hammerstone or similar hard hammer fabricator.
More complex forms of reduction may produce highly standardized blades, which can then be fashioned into a variety of tools such as scrapers, knives, sickles, and microliths.
Archaeologists classify stone tools into industries (also known as complexes or technocomplexes[2]) that share distinctive technological or morphological characteristics.
Consequently, in the literature the stone tools used in the period of the Palaeolithic are divided into four "modes", each of which designates a different form of complexity, and which in most cases followed a rough chronological order.
[12] Grooved, cut and fractured animal bone fossils, made by using stone tools, were found in Dikika, Ethiopia near (200 yards) the remains of Selam, a young Australopithecus afarensis girl who lived about 3.3 million years ago.
These cores were river pebbles, or rocks similar to them, that had been struck by a spherical hammerstone to cause conchoidal fractures removing flakes from one surface, creating an edge and often a sharp tip.
[15] The earliest known Oldowan tools yet found date from 2.6 million years ago, during the Lower Palaeolithic period, and have been uncovered at Gona in Ethiopia.
[16] After this date, the Oldowan Industry subsequently spread throughout much of Africa, although archaeologists are currently unsure which Hominan species first developed them, with some speculating that it was Australopithecus garhi, and others believing that it was in fact Homo habilis.
[citation needed] Eventually, more complex Mode 2 tools began to be developed through the Acheulean Industry, named after the site of Saint-Acheul in France.
[18] The Acheulean first appears in the archaeological record as early as 1.7 million years ago in the West Turkana area of Kenya and contemporaneously in southern Africa.
Then the piece must be worked over again, or retouched, with a soft hammer of wood or bone to produce a tool finely knapped all over consisting of two convex surfaces intersecting in a sharp edge.
Eventually, the Acheulean in Europe was replaced by a lithic technology known as the Mousterian Industry, which was named after the site of Le Moustier in France, where examples were first uncovered in the 1860s.
Evolving from the Acheulean, it adopted the Levallois technique to produce smaller and sharper knife-like tools as well as scrapers.
As humans spread to the Americas in the Late Pleistocene, Paleo-Indians brought with them related stone tools, which evolved separately from Old World technologies.
Such a technology makes much more efficient use of available materials like flint, although required greater skill in manufacturing the small flakes.
These ground or polished implements are manufactured from larger-grained materials such as basalt, jade and jadeite, greenstone and some forms of rhyolite which are not suitable for flaking.
Because of their coarse surfaces, some ground stone tools were used for grinding plant foods and were polished not just by intentional shaping, but also by use.
Polished stone axes were important for the widespread clearance of woods and forest during the Neolithic period, when crop and livestock farming developed on a large scale.
[citation needed] During the Neolithic period, large axes were made from flint nodules by knapping a rough shape, a so-called "rough-out".
[25] There were many sources of supply, including Grimes Graves in Suffolk, Cissbury in Sussex and Spiennes near Mons in Belgium to mention but a few.
[26] Apart from being used as weapons and for cutting, grinding (grindstones), piercing and pounding, some stones, notably ochres, were used as pigment for painting.
[28] The invention of the flintlock gun mechanism in the sixteenth century produced a demand for specially shaped gunflints.
For specialist purposes glass knives are still made and used today, particularly for cutting thin sections for electron microscopy in a technique known as microtomy.
