Obsidian is a naturally occurring volcanic glass formed when lava extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock.
Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Flint was widely used historically to make stone tools and start fires.
Chert is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline 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, 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 lithic analysis, a subdivision of archaeology, a bulb of applied force is a defining characteristic of a lithic flake. Bulb of applied force was first correctly described by Sir John Evans, the cofounder of prehistoric archeology. However, bulb of percussion was coined scientifically by W.J. Sollas. When a flake is detached from its parent core, a portion of the Hertzian cone of force caused by the detachment blow is detached with it, leaving a distinctive bulb on the flake and a corresponding flake scar on the core. In the case of a unidirectional core, the bulb of applied force is produced by an initiated crack formed at the point of contact, which begins producing the Hertzian cone. The outward pressure increases causing the crack to curve away from the core and the bulb formation. The bulb of applied force forms below the striking platform as a slight bulge. If the flake is completely crushed the bulb will not be visible. Bulbs of applied force may be distinctive, moderate, or diffuse, depending upon the force of the blow used to detach the flake, and upon the type of material used as a fabricator. The bulb of applied force can indicate the mass or density of the tool used in the application of the force. The bulb may also be an indication of the angle of the force. This information is helpful to archaeologists in understanding and recreating the process of flintknapping. Generally, the harder the material used as a fabricator, the more distinctive the bulb of applied force. Soft hammer percussion has a low diffuse bulb while hard hammer percussion usually leaves a more distinct and noticeable bulb of applied force. Pressure flake also allowed for diffuse bulbs. The bulb of percussion of a flake or blade is convex and the core has a corresponding concave bulb. The concave bulb on the core is known as the negative bulb of percussion. Bulbs of applied force are not usually present if the flake has been struck off naturally. This allows archaeologists to identify and distinguish natural breakage from human artistry. The three main bulb types are flat or nondescript, normal, and pronounced. A flat or nondescript bulb is poorly defined and does not rise up on the ventral surface. A normal bulb on the ventral side has average height and well-defined. A pronounced bulb rises up on ventral side and is very large.
In archaeology, a tool stone is a type of stone that is used to manufacture stone tools, or tools that use stone as raw material.
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.
Knapping is the shaping of flint, chert, obsidian, or other conchoidal fracturing stone through the process of lithic reduction to manufacture stone tools, strikers for flintlock firearms, or to produce flat-faced stones for building or facing walls, and flushwork decoration. The original Germanic term knopp meant to strike, shape, or work, so it could theoretically have referred equally well to making statues or dice. Modern usage is more specific, referring almost exclusively to the hand-tool pressure-flaking process pictured. It is distinguished from the more general verb "chip" and is different from "carve", and "cleave".
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.
Fracture is the appearance of a crack or complete separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displacement develops perpendicular to the surface, it is called a normal tensile crack or simply a crack; if a displacement develops tangentially, it is called a shear crack, slip band, or dislocation.
Zoisite, first known as saualpite, after its type locality, is a calcium aluminum hydroxy sorosilicate belonging to the epidote group of minerals. Its chemical formula is Ca2Al3(SiO4)(Si2O7)O(OH).
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.
Chrysoprase, chrysophrase or chrysoprasus is a gemstone variety of chalcedony that contains small quantities of nickel. Its color is normally apple-green, but varies to deep green. The darker varieties of chrysoprase are also referred to as prase.
Hyalite is a transparent form of opal with a glassy lustre. It may exhibit an internal play of colors if natural inclusions are present. It is also called Muller's glass, water opal, and jalite. Müller's glass is named after its discoverer, Franz-Joseph Müller von Reichenstein.
In archaeology, lithic technology includes a broad array of techniques used to produce usable tools from various types of stone. The earliest stone tools to date have been found at the site of Lomekwi 3 (LOM3) in Kenya and they have been dated to around 3.3 million years ago. 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.
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.
In sedimentology and geology, a nodule is a small, irregularly rounded knot, mass, or lump of a mineral or mineral aggregate that typically has a contrasting composition, such as a pyrite nodule in coal, a chert nodule in limestone, or a phosphorite nodule in marine shale, from the enclosing sediment or sedimentary rock. Normally, a nodule has a warty or knobby surface and exists as a discrete mass within the host strata. In general, they lack any internal structure except for the preserved remnants of original bedding or fossils. Nodules are closely related to concretions and sometimes these terms are used interchangeably. Minerals that typically form nodules include calcite, chert, apatite (phosphorite), anhydrite, and pyrite.
Samsonite is a silver manganese antimony sulfosalt mineral with formula Ag4MnSb2S6. It crystallizes in the monoclinic crystal system with a typical slender radiating prismatic habit. It is metallic black to steel black with no cleavage and a brittle to conchoidal fracture. In thin fragments it appears reddish brown in transmitted light and also leaves a red streak. It is soft, Mohs hardness of 2.5, and has a specific gravity of 5.51.
In the field of mineralogy, fracture is the texture and shape of a rock's surface formed when a mineral is fractured. Minerals often have a highly distinctive fracture, making it a principal feature used in their identification.
Edoylerite is a rare mercury containing mineral. Edoylerite was first discovered in 1961 by Edward H. Oyler, whom the mineral is named after, in a meter-sized boulder at the Clear Creek claim in San Benito County, California. The Clear Creek claim is located near the abandoned Clear Creek mercury mine. The material from the boulder underwent several analyses including, X-ray powder diffraction (XRD), a single crystal study, and a preliminary electron microprobe analysis (EMA). Using these analyses it was determined that this was a new mineral but the nature of the material at the time prevented further investigation. It was not until 1986, with the discovery of crystals large enough for a crystal structure determination and a sufficient quantity for a full mineralogical characterization, that the study was renewed. The new edoylerite crystals were found in the same area at the Clear Creek claim but were situated in an outcrop of silica-carbonate rock. This silica-carbonate rock was mineralized by cinnabar following the hydrothermal alteration of the serpentinite in the rock. Edoylerite is a primary alteration product of cinnabar. Though found with cinnabar, the crystals of edoylerite do not typically exceed 0.5mm in length. The ideal chemical formula for edoylerite is Hg32+Cr6+O4S2
