Flint biface from Saint-Acheul, France. (20 cm high)

In archaeology, a biface is a two-sided stone tool, manufactured through a process of lithic reduction, that displays flake scars on both sides. Bifacial artifacts can be made on large flakes or blocks, and may be grouped into numerous distinct classes. For the purposes of this article, four classes are defined : Image File history File linksMetadata Download high resolution version (1407x1547, 520 KB) Description dessin de biface en silex de Saint-Acheul (Somme, France) - 20 cm de haut - dessin de A. de Mortillet (fin XIXème) Licensing File links The following pages on the English Wikipedia link to this file (pages... Image File history File linksMetadata Download high resolution version (1407x1547, 520 KB) Description dessin de biface en silex de Saint-Acheul (Somme, France) - 20 cm de haut - dessin de A. de Mortillet (fin XIXème) Licensing File links The following pages on the English Wikipedia link to this file (pages... Pebble beach made up of flint nodules eroded out of the nearby chalk cliffs, Cape Arkona, Rügen Flint (or flintstone) is a hard, sedimentary cryptocrystalline silica rock with a glassy appearance. ... Saint Acheul is a commune of the Somme département. ... Ancient stone tools A stone tool is, in the most general sense, any tool made of stone. ... Lithic reduction involves the use of a hard hammer percussor, such as a hammerstone, a soft hammer fabricator made of wood, bone or antler, or a wood or antler punch to detach lithic flakes from a lump of tool stone called a lithic core. ... In archaeology, a lithic flake is a thin, sharp fragment of stone that results from the process of lithic reduction. ... In archaeology, a lithic flake is a thin, sharp fragment of stone that results from the process of lithic reduction. ...

• Class I consists of large, thick bifaces reduced from cores or thick flakes; these are referred to as blanks.
• Class II consists of thinned blanks. While form remains rough and uncertain, an effort has been made to reduce the thickness of the flake or core.
• Class III bifaces may be either preforms or crude formalized tools, such as adzes.
• Class IV includes the finer formalized tool types such as projectile points and fine bifaces.

It must be emphasized that, while Class IV bifaces are referred to as "formalized tools", bifaces from any stage of a lithic reduction sequence may be used as tools. (Also, other biface typologies make five divisions rather than four) In archaeology, a blank is a thick, shaped stone biface of suitable size and configuration for refining into a stone tool. ... In archaeology, a projectile point is an object that was hafted and used either as knife or projectile tip or both. ...

Bifaces are related to Acheulean industries and appear in East Africa about 1,6 My ago for instance in Olduvai Gorge. They are also known in Mousterian industries. In North America, bifaces make up one of the dominant tool industries from the Early Holocene on. Biface technology is unknown in Australian prehistory. Acheulean (also spelled Acheulian) is the name of an industry of stone tools used by prehistoric hominines. ... Olduvai Gorge from space Topography of Olduvai Gorge The Olduvai Gorge or Oldupai Gorge is a steep-sided ravine in the Great Rift Valley, which stretches along eastern Africa. ... Mousterian is a name given by archaeologists to style of flint tools (or industry) dating to the Palaeolithic or Old Stone Age. ...