sedimentary

Green Chert

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Pale green to olive green; Luster: Waxy to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (shows conchoidal fracture); Specific gravity: 2.65

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

Identified May 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of silica-rich organic remains (like radiolaria or diatoms) or by chemical precipitation in marine environments. Often found in nodules or bedded layers within limestone or shale.

Uses & applications

Historically used for making stone tools (arrowheads, scrapers) due to its sharp fracture edges. Today it is used as a semi-precious gemstone, in landscaping, and as a material for lapidary work.

Geological facts

Chert is so hard it can strike sparks against steel, making it useful for early flintlock firearms. Specific green varieties are sometimes colloquially called 'greenstone' or incorrectly labeled as jade by amateurs.

Field identification & locations

Identify by its waxy texture, extreme hardness (it will scratch glass), and its characteristic shell-like (conchoidal) curved fracture lines when broken. Commonly found in river beds or erosion sites near sedimentary basins.