sedimentary

Chert (Yellow Jasper)

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs Scale); Color: Yellow, tan, mustard; Luster: Waxy to dull; Structure: Cryptocrystalline; Cleavage: None (Conchoidal fracture); Specific Gravity: 2.6-2.65.

Hardness: 6
Color: Yellow, tan, mustard
Luster: Waxy to dull

Identified July 6, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs Scale); Color: Yellow, tan, mustard; Luster: Waxy to dull; Structure: Cryptocrystalline; Cleavage: None (Conchoidal fracture); Specific Gravity: 2.6-2.65.

Formation & geological history

Formed in marine or freshwater environments through the accumulation of silica-rich organic remains or chemical precipitation. This specific yellow color is typically caused by goethite or limonite inclusions.

Uses & applications

Historically used for stone tools (knapping) due to its sharp conchoidal fracture. Modernly used in jewelry making, lapidary arts as 'jasper', and as a collector specimen.

Geological facts

Chert and Jasper are essentially the same mineral, with Jasper being opaque and Chert being the broader geophysical term. Yellow Jasper is often associated with the solar plexus chakra in metaphysical beliefs and has been used for talismans for thousands of years.

Field identification & locations

Identified in the field by its hardness (will scratch glass), waxy feel, and sharp, shell-like (conchoidal) edges when broken. It is a very common material found globally in sedimentary rock layers and riverbeds.