sedimentary
Chert
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness: 6.5-7 Mohs; Color: Brown with white veins; Luster: Dull to waxy; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6
- Hardness
- 6
- Color
- Brown with white veins
- Luster
- Dull to waxy
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Physical properties
Hardness: 6.5-7 Mohs; Color: Brown with white veins; Luster: Dull to waxy; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6
Formation & geological history
Formed primarily as chemical precipitates or through the replacement of limestone by silica-rich fluids. This specimen is a water-worn river pebble or beach stone.
Uses & applications
Historically used for stone tools and weapons (flintknapping); currently used for masonry, road construction, and as decorative river stones.
Geological facts
Chert is one of the most durable sedimentary rocks. When broken, it produces sharp edges which made it the primary material for prehistoric arrowheads and scrapers.
Field identification & locations
Identified in the field by its extreme hardness (scratches glass), smooth texture, and waxy luster. Common in riverbeds and limestone regions.
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