sedimentary
Fossiliferous Chert
Microcrystalline quartz with fossil molds (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and brownish-purple color with distinct small skeletal or fossiliferous cavity molds.
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Physical properties
Hardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and brownish-purple color with distinct small skeletal or fossiliferous cavity molds.
Formation & geological history
Formed through the replacement of limestone or accumulation of siliceous skeletal remains in marine environments over millions of years.
Uses & applications
Used primarily by rock collectors, lapidary display, and educational study of ancient marine environments.
Geological facts
The distinctive holes are fossil molds where ancient marine organisms like crinoids or brachiopods dissolved away, leaving behind hollow casts.
Field identification & locations
Identify by its extreme hardness, waxy luster, and characteristic pitted or vuggy texture filled with fossil impressions. Commonly found in sedimentary creek beds and gravel bars.
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