metamorphic

Rounded pebble, likely quartzite or chert

Quartzite (microcrystalline quartz, SiO₂), tentative identification

AI-generated identification · may be incorrect

Hardness about 7 Mohs; gray-beige, fine-grained, dull to weakly waxy luster, with no visible cleavage and probable conchoidal or irregular fracture. The smooth shape indicates water or abrasion rounding; image detail is insufficient for certainty.

Identified September 7, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely a naturally weathered river or beach pebble derived from quartz-rich rock; quartzite forms when sandstone is metamorphosed under heat and pressure, commonly during mountain-building events. Its exact geological age cannot be determined visually.

Uses & applications

Usually decorative or educational, with little commercial value as an isolated pebble; quartzite is also used as crushed stone, building stone, countertops, and aggregate.

Geological facts

The specimen’s uniform fine texture and high apparent durability fit quartzite, though dense chert, jasper, or a polished industrial stone are alternatives. A steel file should not scratch quartzite; quartz-rich surfaces can scratch glass.

Field identification & locations

Common in river gravels, beaches, glacial deposits, and landscaping stone. Confirm with a hardness test, streak (white), and inspection for translucent quartz grains or conchoidal fracture.