mineral

Rounded quartz-rich pebble

Likely milky quartz (SiO₂), possibly quartzite or a quartz-rich river pebble

AI-generated identification · may be incorrect

White to cream, opaque, dull-to-waxy luster, massive texture, and no obvious cleavage; Mohs hardness about 7, with specific gravity near 2.65. Its smooth, rounded shape indicates natural abrasion or tumbling.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallized from silica-rich igneous or hydrothermal fluids; if quartzite, it formed by metamorphism of quartz sandstone. The pebble was later weathered and rounded in a river, beach, or glacial environment; its precise age cannot be determined visually.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, construction aggregate, and electronics; attractive pieces are sold as curios or lapidary material. It has little jewelry value unless unusually clear or patterned.

Geological facts

Quartz is one of Earth’s most abundant minerals and has strong resistance to weathering, allowing it to survive as rounded pebbles. The specimen may also be a pale chalcedony or calcite, which requires testing to distinguish.

Field identification & locations

Likely locations include streambeds, beaches, glacial deposits, and quartz veins worldwide. Scratch testing with steel or glass, checking for fizz with dilute acid, and examining fracture surfaces can help distinguish quartz from calcite.