chert
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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. Where chert occurs in chalk or marl, it is usually called flint.
Key facts
- Rock.name
- Chert
- Rock.type
- Sedimentary
- Rock.image
- ChertUSGOV.jpg
- Rock.alt
- Chert hand sample
- Rock.caption
- A hand sized sample of chert
- Rock.composition
- Microcrystalline or cryptocrystalline quartz
via Wikipedia infobox
Wikidata facts
- Image
- ChertUSGOV.jpg
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- Commons category
- Chert
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~19 min read
Article
13 sectionsContents
- Description
- Bedded chert
- Subvarieties
- Nodular chert
- Other occurrences
- Fossils
- Prehistoric and historic uses
- Tools
- Construction
- Varieties
- See also
- References
- External links
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. Where chert occurs in chalk or marl, it is usually called flint.
Chert is typically composed of the petrified remains of siliceous ooze, the biogenic sediment that covers large areas of the deep ocean floor, and which contains the silicon skeletal remains of diatoms, silicoflagellates, and radiolarians. Precambrian cherts are notable for the presence of fossil cyanobacteria. In addition to microfossils, chert occasionally contains macrofossils. However, some chert is devoid of any fossils.