sedimentary
Chert (Flint Arrowhead)
Microcrystalline Quartz (SiO2)
Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, translucent; Luster: Waxy to vitreous; Crystal structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
- Hardness
- 6
- Color
- Brown, tan, translucent
- Luster
- Waxy to vitreous
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, translucent; Luster: Waxy to vitreous; Crystal structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
Formation & geological history
Formed as nodules or beds in sedimentary rocks through the precipitation of silica from groundwater or the accumulation of siliceous organisms like diatoms and radiolaria. This specific specimen has been human-worked through percussion and pressure flaking.
Uses & applications
Historically used for stone tools and weapons (arrowheads, scrapers, knives) due to its sharp edges; used today in fire-starting kits and as a collector's item in archaeology and geology.
Geological facts
This specimen is an artifact, specifically a lithic projectile point fragment. Chert/Flint was one of the first materials traded over long distances by prehistoric humans because of its utility and predictability when knapped.
Field identification & locations
Identify in the field by its distinctive waxy texture and conchoidal fracture (curving, shell-like breaks). Often found in limestone or chalk beds. If flaked into a shape, it is an archaeological artifact and should be documented in situ.
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