sedimentary

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale. Color: Brownish-tan to reddish-orange. Luster: Waxy to dull. Crystal Structure: Hexagonal (cryptocrystalline). Cleavage: None, exhibits conchoidal (shell-like) fracture. Specific Gravity: 2.65.

Hardness: 6
Color: Brownish-tan to reddish-orange
Luster: Waxy to dull

Identified May 24, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of silica-rich organic remains or chemical precipitation in sedimentary basins. Often found as nodules in limestone or chalk beds, dating from various geological periods from Precambrian to Cenozoic.

Uses & applications

Historically used for stone tools and weapons due to sharp edges; currently used for decorative stone, lapidary jewelry, and as a component in construction aggregate.

Geological facts

Chert was one of the most important raw materials for early humans; its ability to fracture predictably into razor-sharp edges made it ideal for arrowheads and scrapers. Flint is a specific dark variety of chert.

Field identification & locations

Identify in the field by its distinctive waxy texture and curved, sharp-edged fractures. Commonly found in riverbeds, glacial tills, and outcrops of limestone. Collectors look for unique banding or internal patterns.