sedimentary

Yellow jasper or iron-stained chert

Microcrystalline quartz (SiO₂), commonly colored by iron oxides

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque mustard-yellow to ochre, with a dull to waxy luster and no visible cleavage. The rounded, water-worn shape suggests a pebble; surface texture and internal structure are difficult to confirm from the image.

Identified August 16, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely formed from silica-rich sediment that lithified and recrystallized into chalcedony or microcrystalline quartz, with iron-oxide staining producing the yellow color. Its precise geological age and source locality cannot be determined visually.

Uses & applications

Used for lapidary work, cabochons, beads, carvings, tumbled stones, and decorative objects; occasionally used as a durable aggregate or ornamental stone.

Geological facts

Jasper is an opaque variety of chalcedony, while chert is a closely related microcrystalline quartz rock; field labels often overlap. Yellow coloration commonly comes from limonite or goethite.

Field identification & locations

Test for hardness against glass: genuine jasper/chert should scratch it, though this may damage the specimen. Look for a smooth waxy fracture, lack of cleavage, and resistance to dilute acid; common sources include river gravels and iron-rich sedimentary formations worldwide.