sedimentary

Green Chert

Microcrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Olive green to pistachio green; Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.65.

Hardness: 6
Color: Olive green to pistachio green
Luster: Waxy to vitreous

Identified May 13, 2026More sedimentary →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Olive green to pistachio green; Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.65.

Formation & geological history

Formed via the accumulation of silica-rich organic remains (like radiolarians or diatoms) or chemical precipitation from hydrothermal fluids in marine environments. Most common in Paleozoic or Mesozoic strata.

Uses & applications

Historically used for making stone tools (arrowheads, scrapers); currently used for decorative stone, lapidary projects, and as a collector's specimen.

Geological facts

Chert is essentially a non-banded version of agate or jasper. In some regions, specific green varieties are nicknamed 'Green Flint.' It is incredibly durable and can maintain a sharp edge.

Field identification & locations

Identified by its waxy texture, olive color, and distinct shell-like (conchoidal) fractures. Often found in nodules within limestone or as bedded deposits in oceanic crust sequences.