sedimentary

Chert (Green variety)

Silicon Dioxide (SiO2)

Hardness: 6.5-7.0 (Mohs). Color: Pale to olive green. Luster: Waxy to vitreous. Crystal structure: Cryptocrystalline. Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.6-2.7.

Hardness: 6
Color: Pale to olive green
Luster: Waxy to vitreous

Identified June 13, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7.0 (Mohs). Color: Pale to olive green. Luster: Waxy to vitreous. Crystal structure: Cryptocrystalline. Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.6-2.7.

Formation & geological history

Formed by the accumulation of siliceous remains of organisms like diatoms or radiolarians, or via chemical precipitation from silica-rich fluids. Usually found in deep marine sedimentary environments.

Uses & applications

Historically used for making stone tools due to its sharp fracture edges. Today it is used as decorative stone, in construction aggregates, and for lapidary work.

Geological facts

Green chert is often associated with volcanic sequences where silica is enriched. It is closely related to flint and jasper, differing primarily in color and translucency.

Field identification & locations

Identify in the field by its waxy appearance and smooth, shell-like (conchoidal) breaks. It is harder than steel and will scratch a glass plate. Find it in limestone or dolomite beds.