sedimentary

Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

AI-generated identification · may be incorrect

Hardness: 7 (matrix) to 3 (fossil); Color: Grey/Brown w/ white fossil; Luster: Waxy to vitreous; Structure: Cryptocrystalline; Cleavage: none (conchoidal fracture)

Hardness: 7 (matrix) to 3 (fossil)
Color: Grey/Brown w/ white fossil
Luster: Waxy to vitreous

Identified July 17, 2026More sedimentary →

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Physical properties

Hardness: 7 (matrix) to 3 (fossil); Color: Grey/Brown w/ white fossil; Luster: Waxy to vitreous; Structure: Cryptocrystalline; Cleavage: none (conchoidal fracture)

Formation & geological history

Formed in marine environments via the accumulation of silica-rich organic remains and chemical precipitation, often during the Paleozoic era. The fossil is a marine invertebrate preserved in the rock.

Uses & applications

Geological collecting, educational study, and historical use as tool stones (flint) or decorative lapidary material.

Geological facts

The image shows a distinct brachiopod shell cross-section. Brachiopods have survived for over 500 million years but were most dominant during the Paleozoic era before the Permian-Triassic extinction.

Field identification & locations

Identified by the hard, fine-grained matrix and the characteristic symmetrical shell outline of the brachiopod. Commonly found in limestone and shale deposits globally.