mineral

Tumbled quartz pebble (likely milky quartz)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; off-white to tan, translucent, and typically vitreous to waxy in luster. It has a hexagonal crystal structure, indistinct cleavage, conchoidal fracture, and specific gravity around 2.65; the brown speckles may be iron-oxide staining or inclusions.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich igneous, metamorphic, and hydrothermal fluids, then survives weathering as a durable river or beach pebble. Its exact geological age and locality cannot be determined from the photograph.

Uses & applications

Used in glass, ceramics, electronics, abrasives, countertops, and construction aggregate; attractive pieces are sold as inexpensive lapidary or decorative specimens.

Geological facts

Quartz is one of Earth’s most abundant minerals and commonly forms geodes, veins, sand, and pebbles. Iron staining can produce yellow, tan, or reddish-brown patches.

Field identification & locations

Likely identified by its hardness, glassy fracture, and inability to scratch with a steel knife; it should scratch ordinary glass. Common worldwide in gravel deposits and quartz veins; the image alone cannot exclude a feldspar or weathered jasper pebble.