sedimentary
Chert (often called Flint in archaeological contexts)
Microcrystalline or cryptocrystalline Silica (SiO2)
AI-generated identification · may be incorrectHardness: 7 (Mohs scale); Color: gray, tan, or brown; Luster: waxy to dull; Cleavage: none (conchoidal fracture); Structure: cryptocrystalline.
- Hardness
- 7 (Mohs scale)
- Color
- gray, tan, or brown
- Luster
- waxy to dull
Identified More sedimentary →
Explore Chert (often called Flint in archaeological contexts) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 (Mohs scale); Color: gray, tan, or brown; Luster: waxy to dull; Cleavage: none (conchoidal fracture); Structure: cryptocrystalline.
Formation & geological history
Formed as nodules or beds in sedimentary rocks through the precipitation of silica-rich fluids. This specific piece shows evidence of anthropogenic knapping (flake scars).
Uses & applications
Used historically by indigenous peoples for stone tools (arrowheads, scrapers) due to its sharp edges; used today as a decorative stone, in road base, and as a raw material for silicon.
Geological facts
Chert was one of the most important raw materials for early humans. This specimen is a 'flake' or 'debitage,' a byproduct of making a stone tool.
Field identification & locations
Identify in the field by its shell-like (conchoidal) fracture patterns, sharp edges, and hardness. Often found in limestone or chalk deposits.
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary