sedimentary

Chert (Arrowhead/Tool variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Brownish-red to tan; Luster: Waxy to dull; Crystal structure: Trigonal (microscopic); Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Brownish-red to tan
Luster: Waxy to dull

Identified April 17, 2026More sedimentary →

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Physical properties

Hardness: 7 on Mohs scale; Color: Brownish-red to tan; Luster: Waxy to dull; Crystal structure: Trigonal (microscopic); Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Formed through the accumulation of silica-rich organic remains (like diatoms or radiolarians) or chemical precipitation from groundwater. This specimen appears to have been culturally modified (knapped) into a tool.

Uses & applications

Historically used for making stone tools (arrowheads, scrapers, knives) due to its sharp conchoidal fracture. Modern use includes historical collection and study of lithic technology.

Geological facts

Chert was one of the most vital materials for early humans; it produces edges sharper than steel scalpels when freshly fractured. This specific piece shows signs of human alteration.

Field identification & locations

Identify by its waxy appearance, extreme hardness (it will scratch glass), and the 'scalloped' flake scars typical of conchoidal fracturing. Often found in limestone or chalk beds.