sedimentary

Chert (Jasper)

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs), Color: brown, tan, and reddish, Luster: dull to waxy, Structure: cryptocrystalline, Fracture: conchoidal, Specific Gravity: 2.58-2.91

Hardness: 6

Identified July 3, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs), Color: brown, tan, and reddish, Luster: dull to waxy, Structure: cryptocrystalline, Fracture: conchoidal, Specific Gravity: 2.58-2.91

Formation & geological history

Formed via the accumulation of silica-rich organic remains or chemical precipitation in marine or groundwater environments. The distinct coloration is due to iron impurities.

Uses & applications

Historically used for stone tools; currently used as a decorative stone, in lapidary work (jewelry), and occasionally in industrial abrasives.

Geological facts

This specimen displays 'picture-like' patterns often associated with Jasper. Chert has been used by humans for thousands of years to create sharp-edged blades and arrowheads due to its conchoidal fracturing.

Field identification & locations

Identify by its hardness (scratches glass), waxy luster on fresh breaks, and smooth, curved fracture surfaces. Commonly found in nodules or bedded layers within limestone or dolomite.