sedimentary
Banded Chert / Flint
Microcrystalline Quartz (SiO2)
Hardness 6.5-7 on Mohs scale; waxy to dull luster; pale cream, tan, and greyish-brown banding; smooth, sharp conchoidal fracture; microcrystalline structure.
Identified More sedimentary →
Explore Banded Chert / Flint in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness 6.5-7 on Mohs scale; waxy to dull luster; pale cream, tan, and greyish-brown banding; smooth, sharp conchoidal fracture; microcrystalline structure.
Formation & geological history
Formed through the precipitation of silica-rich fluids in sedimentary environments or by accumulation of siliceous organism remains (like radiolarians or diatoms) during chemical weathering and diagenesis.
Uses & applications
Historically used for knapping tools, arrowheads, and spark-striking flintlock mechanisms. Modern uses include lapidary arts, decorative cabochons, and study specimens.
Geological facts
Banded chert features distinct color layers caused by varying trace mineral impurities during deposition. It fractures with extremely sharp edges, making it essential to early human survival for toolmaking.
Field identification & locations
Identified by high hardness (scratches glass), distinct conchoidal fracturing, waxy surface texture, and visible color banding. Widespread globally, often found in limestone or chalk beds, riverbeds, and gravel deposits.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Shale
Shale (clastic sedimentary rock)
sedimentary
Brown Sandstone (River Rock)
Arenite
sedimentary
Shale
Argillaceous sedimentary rock
sedimentary