Tool stone

{{Short description|Type of stone that is used to manufacture stone tools}}

{{distinguish|Stone tool}}

{{About|tool stone in archaeology|diamond tool stone|diamond tool}}

In archaeology, a tool stone is a type of stone that is used to manufacture stone tools,

{{cite book | first=William | last=Andrefsky Jr. | title=Lithics: Macroscopic Approaches to Analysis | publisher=Cambridge University Press | year=2005 |edition=Second | isbn=0-521-61500-3 }}

or tools that use stone as raw material.

{{cite book

| isbn = 978-1-879621-27-5

| url = https://books.google.com/books?id=8oUIAQAAMAAJ&q=%22tool+stone%22

| title = Folsom lithic technology: explorations in structure and variation

| publisher = International Monographs in Prehistory

| author = Daniel S. Amick

| year = 1999

| access-date = 2010-10-03

}}

Generally speaking, tools that require a sharp edge are made using cryptocrystalline materials that fracture in an easily controlled conchoidal manner.

Cryptocrystalline tool stones include flint and chert, which are fine-grained sedimentary materials; rhyolite and felsite, which are igneous flowstones; and obsidian, 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, see lithic reduction.

Large-grained materials such as basalt, granite and sandstone may also be used as tool stones, but for a very different purpose: they are ideal for ground 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.