sedimentary

Chert (Yellow Jasper)

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs); Color: yellowish-brown, ochre; Luster: waxy to dull; Structure: microcrystalline; Cleavage: none (conchoidal fracture); Specific Gravity: 2.6

Hardness: 6
Color: yellowish-brown, ochre
Luster: waxy to dull

Identified July 17, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: yellowish-brown, ochre; Luster: waxy to dull; Structure: microcrystalline; Cleavage: none (conchoidal fracture); Specific Gravity: 2.6

Formation & geological history

Formed via the accumulation of silica-rich organic remains or chemical precipitation in sedimentary environments. Common in marine or river deposits.

Uses & applications

Historically used for stone tools; currently used in jewelry (lapidary), aquarium decor, and as a collector's specimen.

Geological facts

Yellow jasper is a variety of chalcedony that owes its color to iron oxide (goethite) inclusions. It has been used by humans for thousands of years to create sharp-edged tools.

Field identification & locations

Identify in the field by its hardness (will scratch glass), waxy texture, and smooth, shell-like (conchoidal) breaks. Often found in riverbeds or gravel pits.