sedimentary
Chert Nodule
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically yellowish-brown to grey coloration.
Identified More sedimentary →
Explore Chert Nodule in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically yellowish-brown to grey coloration.
Formation & geological history
Formed through the replacement of limestone or chalk by silica-rich groundwater during the Paleozoic era.
Uses & applications
Historically used for making stone tools and arrowheads due to its sharp edges when fractured.
Geological facts
This specimen's rounded, knobby shape is characteristic of nodules that weather out of limestone formations.
Field identification & locations
Commonly found in sedimentary limestone beds and glacial till; identifiable by its conchoidal fracture and high hardness.
More like this
Other sedimentary specimens
Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion
Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image
fossil
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary