sedimentary

Chert (Flint) Artifact

Silicon Dioxide (SiO2)

Hardness: 7; Color: Dark grey to black; Luster: Waxy to dull; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Opaque.

Hardness: 7
Color: Dark grey to black
Luster: Waxy to dull

Identified July 15, 2026More sedimentary →

Explore Chert (Flint) Artifact in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7; Color: Dark grey to black; Luster: Waxy to dull; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Opaque.

Formation & geological history

Formed as nodules or beds in sedimentary rocks (like limestone or chalk) from the accumulation of silica-rich organic remains or chemical precipitation. This specific piece shows evidence of human modification (knapping and a drilled hole).

Uses & applications

Historically used for stone tools (arrowheads, scrapers) due to its sharp edges. Modern use involves mineral collecting or archaeological study.

Geological facts

This specimen appears to be an archaeological lithic, possibly a flake or tool preform. The circular indentation suggests it may have been used as a spindle socket or was purposefully drilled for suspension or ornamentation.

Field identification & locations

Identify by its flinty, smooth texture and curved, glass-like break patterns. Found in sedimentary basins worldwide. Archaeological specimens should be documented in situ.