sedimentary
Green Chert
Chert (Cryptocrystalline Quartz, SiO2)
Hardness: 7 Mohs, Color: Olive to dark green, Luster: Vitreous to waxy, Structure: Cryptocrystalline, Fracture: Conchoidal, Specific Gravity: 2.6-2.7. It is opaque to translucent.
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 Mohs, Color: Olive to dark green, Luster: Vitreous to waxy, Structure: Cryptocrystalline, Fracture: Conchoidal, Specific Gravity: 2.6-2.7. It is opaque to translucent.
Formation & geological history
Formed in marine environments from the accumulation of silica-rich organic remains such as radiolaria or diatoms. It can also form via chemical precipitation. Commonly found in sedimentary layers of deep-sea origin.
Uses & applications
Historically used for stone tools and arrowheads. Currently used as an ornamental stone, in aquarium decor, or as a lapidary material for jewelry like cabochons.
Geological facts
Green chert gets its color from chlorite or iron inclusions. Because of its conchoidal fracture, it was one of the most important materials for weapon-making in human prehistory alongside obsidian.
Field identification & locations
Identify by its extreme hardness (scratches glass), waxy luster, and shell-like (conchoidal) fracture edges. Commonly found in coastal areas or mountain ranges containing ancient seafloor sediment.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite
sedimentary