sedimentary

Possible iron-stained chert (flint)

Microcrystalline quartz (SiO₂), likely colored by iron oxides

AI-generated identification · may be incorrect

Opaque tan, brown, and rust-red specimen with a dull to slightly waxy surface and irregular, possibly conchoidal fracture. Quartz hardness is 7 Mohs; crystal structure is too fine-grained to see, with no obvious cleavage. Identification from the image is uncertain.

Identified October 13, 2026More sedimentary →

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Physical properties

Formation & geological history

Chert forms when silica accumulates and hardens in sedimentary settings; iron oxides can produce reddish-brown staining. Its age and exact formation environment cannot be determined from the image.

Uses & applications

Chert has historically been used for tools and may be collected as a specimen; this piece appears to have no evident commercial or gem use.

Geological facts

A fresh break in chert often shows curved, shell-like fracture surfaces and sharp edges.

Field identification & locations

Look for hardness near 7, lack of cleavage, and conchoidal fracture; common occurrences include sedimentary beds and limestone. A closer view of a fresh surface or a hardness test would help confirm the identification.