sedimentary

Likely flint (chert) fragment

Microcrystalline quartz (SiO₂), variety chert

AI-generated identification · may be incorrect

Tan-brown, opaque to slightly translucent at thin edges, with a dull to waxy luster and irregular, possibly conchoidal fracture. Quartz hardness is about 7 Mohs; crystal structure is trigonal but crystals are microscopic, with no cleavage.

Identified October 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Chert forms when silica accumulates and replaces or fills sediment in marine or other sedimentary settings; it may be millions to hundreds of millions of years old. The image does not show enough detail to determine its precise age or source.

Uses & applications

Chert has historically been knapped for tools and fire-starting; common fragments are mainly collected or studied rather than used as gemstones or building stone.

Geological facts

Its sharp fracture edges made flint valuable for prehistoric blades and points. The pictured piece is small and appears unworked, though the image alone cannot confirm the identification.

Field identification & locations

Look for a smooth, waxy-looking surface and curved, shell-like fracture; chert commonly occurs in limestone, chalk, and sedimentary beds. Similar-looking quartz-rich materials can be difficult to distinguish from a photo.