mineral

Yellow jasper (likely iron-stained chert or quartzite)

Microcrystalline quartz, SiO₂, colored by iron oxides/hydroxides

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque mustard-yellow to brown, earthy/waxy luster, very fine-grained crystalline structure, and no visible cleavage. It should produce a sharp edge and scratch glass, though the rounded surface suggests tumbling or water wear.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids replace or cement sediments, with iron staining producing the yellow coloration; commonly Paleozoic to younger, though age cannot be determined visually. The specimen appears naturally rounded or polished.

Uses & applications

Used as a lapidary and decorative stone for cabochons, beads, carvings, and tumbled stones; occasionally used as aggregate or ornament. Common pieces generally have modest collector value.

Geological facts

Jasper is an opaque variety of chalcedony or microcrystalline quartz, and color patterns often reflect changing iron-rich fluids during formation.

Field identification & locations

Common in volcanic and sedimentary terrains worldwide, including the western United States, Brazil, India, Madagascar, and Australia. Confirm with a glass-scratch test, streak test, and close inspection for a conchoidal fracture; avoid confusing it with yellow calcite, which is softer.