metamorphic

Tumbled quartzite or quartz-rich river pebble

Quartzite; predominantly microcrystalline SiO₂

AI-generated identification · may be incorrect

Hardness about 7 Mohs; pale honey-yellow, opaque to slightly translucent, with a smooth tumbled surface and dull-to-waxy luster. Quartz grains are tightly interlocked, with no obvious cleavage and specific gravity near 2.65.

Identified September 4, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely a naturally rounded and/or tumbled quartzite pebble, formed when quartz-rich sandstone recrystallized under metamorphic heat and pressure. The yellow color may result from iron-oxide staining; its precise geological age and locality cannot be determined from the image.

Uses & applications

Commonly used as landscaping stone, aggregate, decorative pebble, and lapidary material; attractive pieces may be polished for cabochons or display.

Geological facts

Quartzite is generally more resistant to weathering than its parent sandstone and commonly breaks across grains rather than around them.

Field identification & locations

Test with a steel file or knife: genuine quartzite should resist scratching, while calcite-rich lookalikes will scratch easily. Common in river gravels and metamorphic terrains worldwide.