sedimentary

Chert (Arrowhead/Projectile Point)

Cryptocrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 Mohs; Color: Tan, white, and grey; Luster: Waxy to dull; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Opaque.

Hardness: 6
Color: Tan, white, and grey
Luster: Waxy to dull

Identified July 15, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Tan, white, and grey; Luster: Waxy to dull; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Opaque.

Formation & geological history

Formed as nodules or beds in limestone or chalk through the accumulation of siliceous organisms or silica precipitation. This specimen has been anthropogenically modified by flintknapping, likely during the Archaic or Woodland period.

Uses & applications

Historically used for tools and weapons (arrowheads, scrapers, knives) due to its sharp edges; currently valued by archaeologists and lithic collectors.

Geological facts

Chert is one of the most common materials used by early humans for stone tools. The intentional shaping visible here is called 'pressure flaking', which creates the serrated edges and point.

Field identification & locations

Identify in the field by looking for conchoidal (shell-like) fracture scars and symmetrical shaping. Commonly found in creek beds or plowed fields near ancient water sources or flint outcrops.