sedimentary

Chert (Red Jasper variant)

Silica (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale. Color: Deep reddish-brown (hematite inclusions) with translucent gray/white core. Luster: Waxy to dull. Crystal structure: Cryptocrystalline. Cleavage: None (conchoidal fracture).

Hardness: 7 on Mohs scale
Luster: Waxy to dull

Identified July 1, 2026More sedimentary →

Explore Chert (Red 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

Formation & geological history

Formed through the accumulation of silica-rich microfossils (radiolaria or diatoms) or chemical precipitation in marine environments. The red color suggests the presence of iron oxide during formation.

Uses & applications

Historically used for stone tools due to sharp edges; currently used for lapidary work, jewelry, landscaping, and as a collector's specimen.

Geological facts

Chert has been used by humans for millions of years to create arrowheads and scrapers. Red jasper is often considered a spiritual stone in various cultures, symbolizing grounding and strength.

Field identification & locations

Identify by its characteristic conchoidal (shell-like) fracture and high hardness (it will scratch glass). Commonly found in sedimentary basins or as nodules in limestone. Collectors look for smooth, waxy surfaces and vibrant colors.