Ground stone
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. Organic and inorganic materials are processed on ground stones into edible products. They are sometimes the only artefacts preserved on archaeological sites and are found worldwide.
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