sedimentary

Chert (Jasper-like Silicate)

Microcrystalline quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale. Color: Tan, brown, and yellowish-grey with earthy coating. Luster: Dull to waxy. Crystal structure: Cryptocrystalline. Cleavage: None (conchoidal fracture). Specific gravity: 2.6-2.7.

Hardness: 6
Color: Tan, brown, and yellowish-grey with earthy coating
Luster: Dull to waxy

Identified May 21, 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 environments. Can be found in nodules within limestone or as massive bedded deposits. Geological age varies from Precambrian to modern.

Uses & applications

Historically used for stone tools (arrowheads/scrapers) due to sharp edges; used today as a decorative stone, in construction aggregate, or as an abrasive.

Geological facts

Chert was one of the most important minerals for early humans because its conchoidal fracture creates edges sharper than a steel scalpel. It is highly resistant to chemical weathering.

Field identification & locations

Identify by its hardness (it will scratch glass), its sharp angular edges when broken, and its smooth, waxy interior surface if chipped. Commonly found in riverbeds or within limestone outcrops.