sedimentary

Green Chert

Microcrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Pale green to olive; Luster: Waxy to dull; Crystal structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7.

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

Identified May 25, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Pale green to olive; Luster: Waxy to dull; Crystal structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7.

Formation & geological history

Formed primarily in deep-sea environments from the accumulation of siliceous remains of microscopic organisms (like radiolarians) or through the chemical precipitation of silica.

Uses & applications

Historically used for making stone tools due to its sharp edges; currently used for lapidary work, decorative pebbles, and landscaping.

Geological facts

In the past, green chert was sometimes mistaken for low-grade jade. It is a very durable rock that can withstand significant weathering.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its smooth waxy feel, and its characteristic curved, shell-like (conchoidal) fracture edges. Commonly found in riverbeds or coastal areas where sedimentary layers have eroded.