sedimentary

Yellow Jasper (Chert)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Yellowish-brown to tan; Luster: Waxy to dull; Crystal structure: Trigonal (Microcrystalline); Cleavage: None (Conchoidal fracture); Specific gravity: 2.58-2.91

Hardness: 6
Color: Yellowish-brown to tan
Luster: Waxy to dull

Identified June 30, 2026More sedimentary →

Explore Yellow Jasper (Chert) 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 (Mohs); Color: Yellowish-brown to tan; Luster: Waxy to dull; Crystal structure: Trigonal (Microcrystalline); Cleavage: None (Conchoidal fracture); Specific gravity: 2.58-2.91

Formation & geological history

Formed through the accumulation of silica-rich microfossils or precipitation from hydrothermal fluids in sedimentary environments. Common in ancient seafloor deposits.

Uses & applications

Primarily used for lapidary work, jewelry (beads and cabochons), and as a collector's stone. Historically used for making tools due to its sharp conchoidal fracture.

Geological facts

Jasper is an opaque variety of chalcedony. The name 'jasper' comes from the Greek word 'iaspis', meaning 'spotted stone'. It was highly esteemed in the ancient world for its supposed healing properties.

Field identification & locations

Identify by its waxy luster, smoothness (if water-worn), and inability to be scratched by a steel blade. Found in riverbeds, beaches, and desert washes worldwide.