- Tool stone
In
archaeology , a tool stone is a type of stone that is used to manufacturestone tool s. Generally speaking, tools that require a sharp edge are made usingcryptocrystal line materials that fracture in an easily-controlled conchoidal manner. Cryptocrystalline tool stones includeflint andchert , which are fine-grainedsedimentary materials;rhyolite andfelsite , which areigneous flowstone s; andobsidian , a form of natural glass created by igneous processes. These materials fracture in a predictable fashion, and are easily resharpened. For more information on this subject, seelithic reduction .Large-grained materials, such as
basalt ,granite , andsandstone , may also be used as tool stones, but for a very different purpose: they are ideal forground stone artifacts. Whereas cryptocrystalline materials are most useful for killing and processing animals, large-grained materials are usually used for processing plant matter. Their rough faces often make excellent surfaces for grinding plant seeds. With much effort, some large-grained stones may be ground down into awls, adzes, and axes.References
*cite book | first=William | last=Andrefsky Jr. | title=Lithics: Macroscopic Approaches to Analysis | publisher=Cambridge University Press | year=2005 |edition=Second Edition | id=ISBN-10 0-521-61500-3
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