Hard, dense chemical sedimentary rock composed of microcrystalline quartz. Flint is the dark variety in chalk. Texture: Cryptocrystalline. Rock type: Sedimentary Chemical. Grain size: Microscopic. Minerals present: Microcrystalline quartz chalcedony. Formation: Forms from precipitation of dissolved silica or replacement of carbonate by silica during diagenesis. Common geological settings: Worldwide; found as nodules in limestone flint and as bedded chert in deep marine sequences. Common look-alikes and related entries: Flint, Jasper, Quartzite.
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GeoMiner
Last updated
2026-03-30T14:38:30.083394+00:00
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Published; not independently peer-reviewed
Rocks — U.S. National Park Service. Authoritative overview of rock groups, the rock cycle, and geologic processes.
Hard, dense chemical sedimentary rock composed of microcrystalline quartz. Flint is the dark variety in chalk.
How can you identify Chert Rock?
Compare several properties rather than relying on colour alone. This entry records rock type: Sedimentary Chemical; texture: Cryptocrystalline; grain size: Microscopic; common minerals: Microcrystalline quartz chalcedony. Confirm an important identification with additional field tests or qualified laboratory work.
How does Chert Rock form?
Forms from precipitation of dissolved silica or replacement of carbonate by silica during diagenesis.
Where is Chert Rock commonly found?
Worldwide; found as nodules in limestone flint and as bedded chert in deep marine sequences.
What is Chert Rock commonly confused with?
Chert Rock may be confused with Flint, Jasper, Quartzite. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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