mineral

Tumbled quartz-rich pebble, likely milky quartz with iron staining

Predominantly silicon dioxide (SiO₂), likely quartz; exact rock type cannot be determined from the image alone

AI-generated identification · may be incorrect

Rounded and polished, mottled white, gray, and ochre-brown; vitreous to dull luster. Quartz has Mohs hardness 7, a trigonal crystal system, no cleavage, and specific gravity about 2.65.

Identified October 16, 2026More mineral →

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Physical properties

Rounded and polished, mottled white, gray, and ochre-brown; vitreous to dull luster. Quartz has Mohs hardness 7, a trigonal crystal system, no cleavage, and specific gravity about 2.65.

Formation & geological history

Quartz formed as silica crystallized in veins or cooled from silica-rich fluids; brown coloration commonly comes from iron-oxide staining. The pebble was naturally rounded by water or abrasion, then tumbled; its geological age and source are not identifiable visually.

Uses & applications

Commonly collected as a decorative tumbled stone, used in crafts and jewelry; quartz also has major industrial uses in glass and electronics.

Geological facts

Quartz is one of Earth’s most abundant minerals and resists weathering, allowing it to persist in river and beach gravels.

Field identification & locations

Look for hardness sufficient to scratch glass and no obvious cleavage; iron staining produces yellow-to-brown patches. Similar pebbles occur in quartz veins and many river or coastal gravels worldwide.