Chert

Chert

Chert is a type of rock that includes flint, agate and quartz. It sometimes has fossils in it, usually shells.

It is a sedimentary rock, and it is very hard. Sedimentary rock is formed when sediments are compacted and cemented over a long period of time.

Historically, chert was used to make arrow heads because it forms hard and sharp edges when broken.

The color of chert is usually white or gray, but can be red, yellow or dark grey. If there is a lot of iron oxide in the chert it can be dark red; this type of chert is called "jasper."

Chert Media

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  Chert (dark bands) in the Devonian Corriganville-New Creek limestone, Everett, Pennsylvania

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  Folded beds of chert comprising the Late Permian to Jurassic-aged Liminangcong Formation at Busuanga, Palawan, Philippines

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  Chert nodule within soft limestone at Akçakoca, Turkey

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  Flint with white weathered crust

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  An erosion resistant layer of chert in the Eocene Ping Chau Formation, Hong Kong

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  Mill Creek chert from the Parkin Site in Arkansas