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Obsidian was valued in Stone Age cultures because, like flint, it could be fractured to produce sharp blades or arrowheads in a process called knapping. Like all glass and some other naturally occurring rocks, obsidian breaks with a characteristic conchoidal fracture. It was also polished to create early mirrors.
For stone tools and flintlock strikers, chert is worked using a fabricator such as a hammerstone to remove lithic flakes from a nucleus or core of tool stone. Stone tools can then be further refined using wood, bone, and antler tools to perform pressure flaking. For building work a hammer or pick is used to split chert nodules supported on the lap.
Flaked stone reduction involves the use of a hard hammer percussor, such as a hammerstone, a soft hammer fabricator (made of wood, bone or antler), or a wood or antler punch to detach lithic flakes from the lithic core. As flakes are detached in sequence, the original mass of stone is reduced; hence the term for this process.
The log structure was made at least 476,000 years ago, while the wood tools are slightly younger, under 400,000 years old. That places the materials in a time before our species, Homo sapiens ...
Mottes are mound structures made of earth and stone that once held castles. They are an important part of the motte-and-bailey castle , a castle design during early Norman times in which the castle is built on the motte, and surrounded by a ditch and a bailey , which is an enclosure with a stone wall.
This is a unique type of lithic reduction, as only a single side of the stone is retouched to produce the cutting surface of the stone. The side that does not do the cutting is left unscathed, an unusual practice. These old instruments were made from specific materials. Initially, they were composed of quartz, quartzite, basalt, or obsidian.
Rock cupules (/ ˈ k j uː p j uː l /) are artificially made depressions on rock surfaces that resemble the shape of an inverse spherical cap or dome. [1] They were made by direct percussion with hand-held hammer-stones, on vertical, sloping or horizontal rock surfaces.
U.S. President Donald Trump said he planned to invoke the Alien Enemies Act as part of his pledge to deport millions of people who are in the country illegally. The Alien Enemies Act was enacted ...