sedimentary

Banded Chert

Banded Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale; Color: Gray, white, and black bands; Luster: Dull to waxy; Texture: Fine-grained, smooth water-worn surface; Cleavage: None (conchoidal fracture)

Hardness: 6
Color: Gray, white, and black bands
Luster: Dull to waxy

Identified July 19, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Gray, white, and black bands; Luster: Dull to waxy; Texture: Fine-grained, smooth water-worn surface; Cleavage: None (conchoidal fracture)

Formation & geological history

Formed in marine environments through the accumulation of silica-rich organic remains or chemical precipitation. These stones often acquire their rounded, smooth shape through river or ocean wave erosion.

Uses & applications

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

Geological facts

Chert was one of the most important materials for early humans to create arrowheads and knives. Banded varieties like this one are often referred to as 'ribbon chert' or 'striped pebbles'.

Field identification & locations

Identified by its waxy luster, hardness (it can scratch glass), and fine-grained texture. Commonly found in riverbeds, glacial tills, and along coastlines where sedimentary layers are exposed.