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Chert (/ tʃ ɜːr t /) is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, [1] the mineral form of silicon dioxide (SiO 2). [2] Chert is characteristically of biological origin, but may also occur inorganically as a chemical precipitate or a diagenetic replacement, as in petrified wood.
The notched version was probably hafted as a spade. Another advantageous property of the Mill Creek chert was the large size of the nodules, which meant that the corresponding tools could be large. Some hoes were up to 60 centimetres (24 in) in length. [4] The other main use for the chert was large ceremonial bifaces, spatulate celts and stone ...
The Gunflint chert (1.88 Ga [1]) is a sequence of banded iron formation rocks that are exposed in the Gunflint Range of northern Minnesota and northwestern Ontario along the north shore of Lake Superior. The Gunflint Chert is of paleontological significance, as it contains evidence of microbial life from the Paleoproterozoic. [2]
Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, [1] [2] categorized as the variety of chert that occurs in chalk or marly limestone. Historically, flint was widely used to make stone tools and start fires. Flint occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones.
The Munsungan-Chase Lake Thoroughfare Archeological District encompasses a series of important archaeological sites in a remote area of northern Maine, United States.These sites offer evidence of human habitation dating to not long after the retreat of the glaciers following the Wisconsin glaciation, with extensive stone tool workshops working with red chert found in abundance in the area.
The Rhynie chert is a Lower Devonian [1] sedimentary deposit exhibiting extraordinary fossil detail or completeness (a Lagerstätte). [2] It is exposed near the village of Rhynie, Aberdeenshire , Scotland ; a second unit, the Windyfield chert , is located some 700 m away.
For example, concretions in sandstones or shales are commonly formed of a carbonate mineral such as calcite; those in limestones are commonly an amorphous or microcrystalline form of silica such as chert, flint, or jasper; while those in black shale may be composed of pyrite. [18]
Dover chert "swords" similar to objects in the Duck River cache, found at the Etowah Mounds site in Georgia. The cache has been called "perhaps the most spectacular single collection of prehistoric Native American art ever discovered in the eastern United States". [2] "