sedimentary

Yellow jasper (likely iron-stained chert)

Microcrystalline quartz (SiO₂), chiefly chalcedony/quartz with iron-oxide pigments

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; mustard-yellow, opaque, and waxy to dull luster with a fine, massive texture. No visible cleavage; conchoidal fracture is expected, with specific gravity near 2.6.

Identified September 18, 2026More sedimentary →

Explore Yellow jasper (likely iron-stained 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 about 6.5–7 Mohs; mustard-yellow, opaque, and waxy to dull luster with a fine, massive texture. No visible cleavage; conchoidal fracture is expected, with specific gravity near 2.6.

Formation & geological history

Forms when silica-rich groundwater replaces or cements sediment, commonly incorporating goethite or hematite that produces the yellow color. It may range from Paleozoic to Cenozoic in age depending on locality.

Uses & applications

Used as ornamental stone, cabochons, beads, carvings, and tumbled specimens; too small here for construction use.

Geological facts

Jasper is an opaque variety of chalcedony/chert rather than a single strictly defined mineral. Yellow coloration commonly reflects hydrated iron oxides.

Field identification & locations

Identify by its opaque fine grain, silica-like hardness, and inability to scratch with a steel knife; it should scratch glass, though this test can damage the specimen. Common in volcanic and sedimentary terrains worldwide, including the western United States, Brazil, India, and Madagascar.