mineral

Rounded quartz-rich pebble

Likely quartz-bearing chert or weathered quartzite; composition primarily SiO₂

AI-generated identification · may be incorrect

Gray-beige, rounded and fine-grained with a dull to slightly glassy luster; likely hardness about 6.5–7 Mohs, no obvious cleavage, and moderate-to-high density (approximately 2.6 g/cm³). The visible pits and mottling may reflect weathering or minor iron-oxide inclusions.

Identified September 5, 2026More mineral →

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Physical properties

Formation & geological history

Probably a naturally water-worn clast eroded from quartzite, chert, or silicified rock and deposited in a gravelly stream or beach environment. Its precise geological age cannot be determined from the photograph.

Uses & applications

Common examples have little commercial value and are used as landscaping gravel, aggregate, or curios; attractive patterned pieces may be polished for small decorative objects.

Geological facts

Quartz-rich rocks resist weathering, so they commonly survive transport as rounded pebbles. A streak, hardness test, and close examination of fracture surfaces would help distinguish quartzite from chert.

Field identification & locations

Look for inability to scratch it with a steel knife, lack of fizzing in dilute hydrochloric acid, and a white streak; quartzite usually shows interlocking visible grains, whereas chert is more uniformly waxy and microcrystalline. Common in streambeds, beaches, glacial deposits, and gravel pits.