sedimentary

Chert (Arrowhead or Flake)

Microcrystalline quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Grayish-green to translucent; Luster: Waxy to vitreous; Structure: Microcrystalline with conchoidal (shell-like) fracture; Cleavage: None.

Hardness: 7 on Mohs scale
Color: Grayish-green to translucent
Luster: Waxy to vitreous

Identified June 19, 2026More sedimentary →

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Physical properties

Hardness: 7 on Mohs scale; Color: Grayish-green to translucent; Luster: Waxy to vitreous; Structure: Microcrystalline with conchoidal (shell-like) fracture; Cleavage: None.

Formation & geological history

Formed as chemical precipitates in marine environments or through the replacement of limestone. This specific piece shows signs of anthropogenic modification (pressure flaking), suggesting it was worked by humans into a tool or projectile point.

Uses & applications

Historically used for stone tools (knives, arrowheads, scrapers) due to its sharp edges. Modernly used in construction aggregate and as a collector's item.

Geological facts

Chert breaks with a conchoidal fracture, creating edges that are sharper than a surgical scalpel. This specimen appears to be an artifact, specifically a lithic flake or the base of an arrowhead.

Field identification & locations

Identify in the field by its waxy texture and shell-like curved breaks. Found globally in limestone beds or as river cobbles. Look for 'scars' from where flakes were removed by early humans.