sedimentary

Iron-rich chert or jasper pebble

Microcrystalline quartz (SiO₂), colored by iron oxides

AI-generated identification · may be incorrect

Typically hardness ~6.5–7 Mohs, opaque reddish-brown with dark gray areas, dull to waxy luster, and conchoidal fracture; no visible cleavage. The rounded surface indicates water tumbling or sediment transport.

Identified August 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely formed when silica-rich groundwater replaced or cemented sediment, with iron oxides producing the red-brown color. Chert and jasper range from Precambrian to recent and occur in many sedimentary environments.

Uses & applications

Used as aggregate, road gravel, landscaping stone, flint-like material, and occasionally in cabochons or polished decorative pieces. This small weathered pebble has little commercial value.

Geological facts

The image does not show diagnostic crystals or layering, so exact identification is uncertain; it could also be a weathered ironstone or volcanic rock. A fresh conchoidal break and a scratch test help distinguish it from softer alternatives.

Field identification & locations

Common in gravel beds, stream deposits, beaches, and jasper-bearing regions worldwide. It should resist scratching by a steel knife and may scratch glass; a streak test is usually weak or absent.