 Stone tool, the 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 age cultures that have become extinct. Stone tools 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. Stone has been used to make a wide variety of different tools throughout history, including arrowheads, spear points and quarts. Stone tools may be made of either ground stone or chipped stone, and a person who creates tools out of the latter is known as a flintnapper. Chipped stone tools are made from cryptocrystalline materials such as chert or flint, radiolatterite, calcetane, obsidian, basalt, and quartzite via a process known as lithic reduction. One simple form of reduction is to strike stone planks from a nucleus court of material using the hammer stone or similar hard hammer fabricator. If the goal of the reduction strategy is to produce planks, the remnant lithic or may be discarded once it has become too small to use. In some strategies, however, the flintnapper reduces the core to a rough unit facial or bifacial preform, which is further reduced using soft hammer flaking techniques or by pressure flaking the edges. More complex forms of reduction include the production of highly standardized blades, which can then be fashioned into a variety of tools such as scrapers, knives, sickles and microlips. In general terms, chipped stone tools are nearly ubiquitous in all pre-metal using societies because they are easily manufactured, the tool stone is usually plentiful, and they are easy to transport and sharpen.