mineral

Tumbled quartz-rich pebble

Microcrystalline quartz (SiO₂), possibly chalcedony or quartzite

AI-generated identification · may be incorrect

Hardness about 7 Mohs; off-white to cream with rusty-yellow iron-oxide staining, dull to waxy luster, and no obvious cleavage. The rounded shape and pitted surface indicate natural abrasion or tumbling; exact identification requires a scratch test and close examination.

Identified August 26, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed as silica-rich vein material, chalcedony, or quartzite, later weathered and rounded in a stream, beach, or tumbler. Its age cannot be determined from the photograph and may range from relatively young sediment to ancient bedrock material.

Uses & applications

Commonly used as a decorative pebble, lapidary material, aggregate, and occasionally in inexpensive carvings or jewelry. Its value is primarily aesthetic rather than commercial.

Geological facts

Rusty areas are likely limonite or hematite coatings produced by oxidation of iron-bearing minerals. Quartz-rich pebbles commonly resist weathering after softer surrounding rock decomposes.

Field identification & locations

Test whether it scratches ordinary glass but not a steel knife; quartz-rich material should do so. Common worldwide, especially in river gravels, beaches, quartz veins, and quartzite terrains.