mineral

Tumbled quartz-rich pebble

Microcrystalline quartz (SiO₂), possibly iron-stained chalcedony

AI-generated identification · may be incorrect

Smooth, rounded pebble with a gray-brown translucent body and rusty reddish-brown inclusions or surface staining. Quartz has Mohs hardness 7, vitreous-to-waxy luster, no cleavage, conchoidal fracture, and specific gravity about 2.65; internal details are insufficient for a precise variety identification.

Identified August 29, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed as quartz or chalcedony in a vein, cavity, or silica-rich sediment, then naturally water-rounded or mechanically tumbled; iron oxidation produced the reddish stains. Its exact geological age and source cannot be determined from the photograph.

Uses & applications

Suitable as a pocket specimen, craft stone, or inexpensive tumbled stone; quartz-rich pebbles are also used as aggregate and silica sources.

Geological facts

Quartz is one of Earth’s most abundant minerals and commonly survives weathering because of its hardness and chemical durability.

Field identification & locations

Test against glass: genuine quartz should scratch it; inspect for conchoidal fracture and a waxy or glassy surface. Common in stream gravels and quartz veins worldwide; visual identification cannot exclude jasper or another silica-rich pebble.