sedimentary

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale; Color: Tan to yellow-brown; Luster: Waxy to dull; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 6
Color: Tan to yellow-brown
Luster: Waxy to dull

Identified June 26, 2026More sedimentary →

Explore Chert (Yellow Jasper variant) in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Tan to yellow-brown; Luster: Waxy to dull; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed via the accumulation of silica-rich organic remains (like radiolarians) or chemical precipitation from hydrothermal fluids within sedimentary layers. This river-worn cobble likely originated in the Paleozoic or Mesozoic era.

Uses & applications

Historically used for stone tools and flintknapping. Today used as decorative landscaping stone, in jewelry (as jasper), and as a gemstone for tumbling.

Geological facts

Chert is essentially the same mineral as flint, but the name ' jasper' is often applied to opaque, colorful varieties. It is extremely durable and can withstand millions of years of river transport.

Field identification & locations

Identify by its smooth, waxy texture and conchoidal (shell-like) fracture patterns. Highly resistant to scratching by steel. Common in riverbeds and glacial till throughout North America.