In
lithic analysis
In archaeology, lithic analysis is the analysis of stone tools and other chipped stone artifacts using basic scientific techniques. At its most basic level, lithic analyses involve an analysis of the artifact’s morphology, the measurement of ...
(a subdivision of
archaeology
Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscap ...
), an eraillure is a flake removed from a
lithic flake
In archaeology, a lithic flake is a "portion of rock removed from an objective piece by percussion or pressure,"Andrefsky, W. (2005) ''Lithics: Macroscopic Approaches to Analysis''. 2d Ed. Cambridge, Cambridge University Press and may also be refe ...
's
bulb of force, which is a lump left on the ventral surface of a flake after it is detached from a core of
tool stone
A tool is an object that can extend an individual's ability to modify features of the surrounding environment or help them accomplish a particular task. Although many animals use simple tools, only human beings, whose use of stone tools dates bac ...
during the process of
lithic reduction
In archaeology, in particular of the Stone Age, lithic reduction is the process of fashioning stones or rocks from their natural state into tools or weapons by removing some parts. It has been intensely studied and many archaeological industries ...
.
[Hiscock, Peter. (1997]
Glossary of Terms used in "Lithic" Analysis."
Australian National University. Retrieved 2011-12-14. The mechanics of eraillure formation are related to the propagation of a
Hertzian cone
A Hertzian cone is the cone produced when an object passes through a solid, such as a bullet through glass. More technically, it is a cone of force that propagates through a brittle, amorphous, or cryptocrystalline solid material from a point of ...
of force through the
cryptocrystal
Cryptocrystalline is a rock microstructure, rock texture made up of such minute crystals that its crystalline nature is only vaguely revealed even microscopically in thin section by transmitted polarized light. Among the sedimentary rocks, chert a ...
line matrix of the stone, but the particulars are poorly understood. Eraillures usually form only when a
hammerstone
In archaeology, a hammerstone is a hard cobble used to strike off lithic flakes from a lump of tool stone during the process of lithic reduction. The hammerstone is a rather universal stone tool which appeared early in most regions of the wo ...
is used for lithic reduction, and then only occasionally; use of 'soft' hammer fabricators made from
bone
A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
,
antler
Antlers are extensions of an animal's skull found in members of the Cervidae (deer) family. Antlers are a single structure composed of bone, cartilage, fibrous tissue, skin, nerves, and blood vessels. They are generally found only on male ...
, and
wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...
produce different flake characteristics but may also produce an eraillure in rare cases.
See also
*
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 ...
References
{{Prehistoric technology
Lithics