sedimentary

Chert (Arrowhead/Projectile Point)

Microcrystalline quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 Mohs; Color: Brown to tan (coated in red iron-rich soil); Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture)

Hardness: 6
Color: Brown to tan (coated in red iron-rich soil)
Luster: Waxy to vitreous

Identified May 28, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Brown to tan (coated in red iron-rich soil); Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture)

Formation & geological history

Formed as nodules in limestone or chalk through the accumulation of siliceous biological remains. This specimen has been anthropogenically modified (knapped) during the prehistoric era.

Uses & applications

Historically used for tools and weapons; today collected as archaeological artifacts and used in lapidary work.

Geological facts

Chert breaks with a conchoidal fracture, creating sharp edges used by ancient humans for thousands of years. This specific piece shows clear 'flake scars' from intentional shaping.

Field identification & locations

Identify by looking for waxy luster and shell-like (conchoidal) fracture patterns. Often found in areas with limestone bedrock or ancient habitation sites. Note: Removing artifacts from public land is often illegal.