sedimentary

Yellow jasper (likely iron-rich chert)

Microcrystalline quartz, SiO₂, colored by iron oxides/hydroxides

AI-generated identification · may be incorrect

Opaque mustard-yellow to brown, wet-looking glossy surface, massive and fine-grained with no visible crystals or cleavage; quartz hardness about 6.5–7 Mohs, vitreous to dull luster, specific gravity about 2.6. The image cannot confirm exact identification; it may also be iron-rich quartzite or silicified rock.

Identified September 21, 2026More sedimentary →

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Physical properties

Formation & geological history

Typically forms when silica-rich fluids replace or cement sediment, with iron minerals producing the yellow-brown color; commonly Precambrian to younger. It occurs as nodules, pebbles, veins, and beds in sedimentary or volcanic terrains.

Uses & applications

Used for lapidary cabochons, carvings, beads, polished stones, and decorative aggregate; generally unsuitable for major structural construction.

Geological facts

Jasper is a variety of opaque, impurity-rich chalcedony or microcrystalline quartz rather than a single mineral species. Yellow coloration commonly reflects goethite or limonite.

Field identification & locations

Look for a hard, opaque, uniform stone that scratches glass and produces a white streak; acid usually causes no reaction. Common in gravel deposits and iron-rich silica formations worldwide.