mineral

Tumbled quartz-rich pebble, likely milky quartz

Quartz (silicon dioxide, SiO₂), possibly iron-stained milky quartz

AI-generated identification · may be incorrect

Hardness 7 Mohs; cream to pale yellow with brown iron-oxide staining, vitreous-to-waxy luster, translucent edges, and no visible cleavage. Quartz is trigonal, though the rounded surface obscures crystal form; density is about 2.65 g/cm³.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Likely weathered from a quartz vein or quartz-rich igneous/metamorphic rock, then naturally rounded or mechanically tumbled; the image does not allow a precise geological age. Brown markings are probably limonite/goethite staining and minor fractures or inclusions.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, electronics, and construction aggregate; attractive polished pieces are sold as inexpensive decorative or lapidary stones.

Geological facts

Quartz is one of Earth’s most abundant minerals and resists weathering, allowing it to persist as rounded stream and beach pebbles. The yellow color may also reflect surface alteration rather than a distinct gemstone variety.

Field identification & locations

Identify by its glassy appearance, lack of cleavage, rounded pebble form, and ability to scratch ordinary glass; a steel file should not scratch it easily. Common in stream gravels, beaches, quartz veins, and quartz-rich sandstones worldwide.