sedimentary

Chert (Jasper variation)

Silicon dioxide (SiO2) - Microcrystalline Quartz

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale), Color: Brown, tan, and yellow with concentric banding (Liesegang rings), Luster: Waxy to dull, Crystal structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific gravity: 2.65

Hardness: 6

Identified June 13, 2026More sedimentary →

Explore Chert (Jasper variation) in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed through the precipitation of silica from groundwater or the accumulation of silica-rich organic debris in sedimentary basins. The banding is caused by the rhythmic precipitation of iron oxides within the stone over geologically long periods.

Uses & applications

Historically used for tool making (arrowheads/knives) due to conchoidal fracture. Modern uses include decorative gravel, lapidary work (cabochons), and as a collector's specimen.

Geological facts

This specimen features Liesegang rings, which are colored bands of cement or precipitates that often look like wood grain or topographical maps. They are common in fine-grained silica-rich rocks like chert and sandstone.

Field identification & locations

Identify in the field by its hardness (will scratch glass), smooth waxy texture, and unique curved patterns. Commonly found in river beds and sedimentary outcrops globally.