Rock Identifier
Tumbled yellow jasper or weathered quartz-rich rock (Microcrystalline quartz (SiO₂), likely jasper with iron-oxide staining and dark inclusions) — mineral
mineral

Tumbled yellow jasper or weathered quartz-rich rock

Microcrystalline quartz (SiO₂), likely jasper with iron-oxide staining and dark inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque cream-yellow body with brown-black mottling, waxy to dull luster, and no visible cleavage. The rounded shape indicates natural abrasion or tumbling; exact identification is limited by the blurred image.

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Physical properties

Hardness about 6.5–7 Mohs; opaque cream-yellow body with brown-black mottling, waxy to dull luster, and no visible cleavage. The rounded shape indicates natural abrasion or tumbling; exact identification is limited by the blurred image.

Formation & geological history

Jasper forms when silica-rich fluids replace or cement sediment, commonly with iron and manganese oxides; formation ages vary widely. It commonly occurs as pebbles in stream gravels, beaches, and weathered volcanic or sedimentary terrains.

Uses & applications

Used for cabochons, beads, carvings, tumbled stones, and decorative objects; lesser material has minimal industrial value.

Geological facts

A steel file or quartz crystal should scratch it, while a fingernail will not. Yellow coloration commonly reflects hydrated iron oxides such as goethite or limonite.

Field identification & locations

Common in gravel deposits worldwide, including western North America, Australia, India, and Brazil; test a fresh spot for hardness and inspect translucency and grain texture to distinguish jasper from yellow quartzite or calcite.