sedimentary

Chert / Jasper

Silicon Dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness: 6.5–7 (Mohs scale); Color: Olive green to brownish-yellow; Luster: Dull to waxy; Structure: Microcrystalline/Cryptocrystalline quartz; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6–2.7

Hardness: 6
Color: Olive green to brownish-yellow
Luster: Dull to waxy

Identified March 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the accumulation of silica-rich organic remains (like diatoms or radiolaria) or chemical precipitation from hydrothermal fluids in sedimentary basins. Hardened over millions of years through lithification.

Uses & applications

Historically used for stone tools (arrowheads). Modernly used for landscaping, jewelry (when polished), and as an abrasive in industrial applications.

Geological facts

This specimen shows the characteristic 'conchoidal' fracture pattern, which creates sharp, curved edges similar to broken glass. This property made it the primary material for prehistoric survival tools.

Field identification & locations

Identify in the field by its hardness (it should scratch glass), smooth texture, and curved breakage lines. Commonly found in riverbeds or as nodules within limestone layers.