In archaeology, a tool stone is a type of stone that is used to manufacture stone tools,or stones used as the raw material for tools.
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.
Sandstone is a clastic sedimentary rock composed mainly of sand-sized silicate grains. Sandstones make up about 20 to 25 percent of all sedimentary rocks.
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at the Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place. The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus. The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or mass movement, which are called agents of denudation. Biological detritus was formed by bodies and parts of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies. Sedimentation may also occur as dissolved minerals precipitate from water solution.
Chert is a hard, fine-grained sedimentary rock composed of microcrystalline (or cryptocrystalline) crystals of quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin but may also occur inorganically as a chemical precipitate or a diagenetic replacement, as in petrified wood.
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 world including Europe, India and North America. This technology was of major importance to prehistoric cultures before the age of metalworking.
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 are identified almost entirely by the lithic analysis of the precise style of their tools and the chaîne opératoire of the reduction techniques they used.
In archaeology, a lithic flake is a "portion of rock removed from an objective piece by percussion or pressure," and may also be referred to as a chip or flake, or collectively as debitage. The objective piece, or the rock being reduced by the removal of flakes, is known as a core. Once the proper tool stone has been selected, a percussor or pressure flaker is used to direct a sharp blow, or apply sufficient force, respectively, to the surface of the stone, often on the edge of the piece. The energy of this blow propagates through the material, often producing a Hertzian cone of force which causes the rock to fracture in a controllable fashion. Since cores are often struck on an edge with a suitable angle (x<90°) for flake propagation, the result is that only a portion of the Hertzian cone is created. The process continues as the flintknapper detaches the desired number of flakes from the core, which is marked with the negative scars of these removals. The surface area of the core which received the blows necessary for detaching the flakes is referred to as the striking platform.
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 cultures that have become extinct. Archaeologists often study such prehistoric societies, and refer to the study of stone tools as lithic analysis. Ethnoarchaeology has been a valuable research field in order to further the understanding and cultural implications of stone tool use and manufacture.
In archaeology, a grinding slab is a ground stone artifact generally used to grind plant materials into usable size, though some slabs were used to shape other ground stone artifacts. Some grinding stones are portable; others are not and, in fact, may be part of a stone outcropping.
In archaeology, ground stone is a category of stone tool formed by the grinding of a coarse-grained tool stone, either purposely or incidentally. Ground stone tools are usually made of basalt, rhyolite, granite, or other cryptocrystalline and igneous stones whose coarse structure makes them ideal for grinding other materials, including plants and other stones.
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 various physical attributes, and examining other visible features.
A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition and the way in which it is formed. Rocks are usually grouped into three main groups: igneous rocks, sedimentary rocks and metamorphic rocks. Rocks form the Earth's outer solid layer, the crust, and most of its interior, except for the liquid outer core and pockets of magma in the asthenosphere.
Mortar and pestle is a set of 2 simple tools used since the stone age up to the present day to prepare ingredients or substances by crushing and grinding them into a fine paste or powder in the kitchen, laboratory, and pharmacy. The mortar is a bowl, typically made of hard wood, metal, ceramic, or hard stone, such as granite. The pestle is a blunt club-shaped object. The substance to be ground, which may be wet or dry, is placed in the mortar, where the pestle is pounding, pressing and rotating onto the substance, until the desired texture is achieved.
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 impact. This force eventually removes a full or partial cone in the material. This is the physical principle that explains the form and characteristics of the flakes removed from a core of tool stone during the process of lithic reduction.
In archaeology, a blade is a type of stone tool created by striking a long narrow flake from a stone core. This process of reducing the stone and producing the blades is called lithic reduction. Archaeologists use this process of flintknapping to analyze blades and observe their technological uses for historical peoples.
The matrix or groundmass of a rock is the finer-grained mass of material in which larger grains, crystals or clasts are embedded.
In archaeology, lithic technology includes a broad array of techniques used to produce usable tools from various types of stone. The earliest stone tools were recovered from modern Ethiopia and were dated to between two-million and three-million years old. The archaeological record of lithic technology is divided into three major time periods: the Paleolithic, Mesolithic, and Neolithic. Not all cultures in all parts of the world exhibit the same pattern of lithic technological development, and stone tool technology continues to be used to this day, but these three time periods represent the span of the archaeological record when lithic technology was paramount. By analysing modern stone tool usage within an ethnoarchaeological context, insight into the breadth of factors influencing lithic technologies in general may be studied. See: Stone tool. For example, for the Gamo of Southern Ethiopia, political, environmental, and social factors influence the patterns of technology variation in different subgroups of the Gamo culture; through understanding the relationship between these different factors in a modern context, archaeologists can better understand the ways that these factors could have shaped the technological variation that is present in the archaeological record.lillith
Use-wear analysis is a method in archaeology to identify the functions of artifact tools by closely examining their working surfaces and edges. It is mainly used on stone tools, and is sometimes referred to as "traceological analysis".
In archaeology, a flake tool is a type of stone tool that was used during the Stone Age that was created by striking a flake from a prepared stone core. People during prehistoric times often preferred these flake tools as compared to other tools because these tools were often easily made, could be made to be extremely sharp & could easily be repaired. Flake tools could be sharpened by retouch to create scrapers or burins. These tools were either made by flaking off small particles of flint or by breaking off a large piece and using that as a tool itself. These tools were able to be made by this "chipping" away effect due to the natural characteristic of stone. Stone is able to break apart when struck near the edge. Flake tools are created through flint knapping, a process of producing stone tools using lithic reduction. Lithic reduction is the removal of a lithic flake from a larger stone in order to reach the desired tool shape and size. The beginning stone is called the flake lithic core. There are three steps to lithic reduction:
Debitage is all the material produced during the process of lithic reduction and the production of chipped stone tools. This assemblage includes, but is not limited to, different kinds of lithic flakes and lithic blades, shatter and production debris, and production rejects.
This glossary of geology is a list of definitions of terms and concepts relevant to geology, its sub-disciplines, and related fields. For other terms related to the Earth sciences, see Glossary of geography terms.