mineral

Yellow-brown jasper or silicified volcanic rock

Microcrystalline quartz (chalcedony), SiO₂, likely jasper

AI-generated identification · may be incorrect

Opaque mustard-yellow to brown material with a dull-to-waxy luster, irregular fracture, and a pale gray host or weathering rind. Quartz hardness is about 6.5–7 Mohs; the visible dark and light zones suggest iron-oxide staining and mixed silica-rich material rather than distinct crystals.

Identified August 16, 2026More mineral →

Explore Yellow-brown jasper or silicified volcanic rock 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

Likely formed when silica-rich fluids replaced or cemented volcanic or sedimentary material, with iron oxides producing the yellow-brown color. Precise age and locality cannot be determined from the photograph.

Uses & applications

Jasper is used for cabochons, carvings, beads, lapidary slabs, and decorative objects; poorer rough is mainly a collector specimen.

Geological facts

Jasper is an opaque variety of chalcedony and commonly shows brecciation, flow-like banding, or replacement textures. The specimen may also be a silicified rhyolite or tuff rather than pure jasper.

Field identification & locations

Test for glass-scratching hardness and inspect a freshly broken or polished surface for uniform microcrystalline silica; acid reaction would suggest carbonate contamination. Common sources include volcanic terrains in the western United States, Mexico, Madagascar, India, and Australia.