sedimentary

Rounded sandstone pebble

Sandstone, commonly quartz-rich arkose or lithic sandstone

AI-generated identification · may be incorrect

Tan, rounded, fine- to medium-grained clastic rock with a dull/earthy luster and likely iron-oxide staining; hardness about 6–7 for quartz grains, but the cement may be weaker. No visible crystals or cleavage; apparent specific gravity roughly 2.2–2.7.

Identified August 30, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand-sized grains—mostly quartz with possible feldspar and rock fragments—were compacted and cemented, likely during burial in a river, beach, or desert environment. Its exact geological age cannot be determined from the photograph.

Uses & applications

Used mainly as a building and landscaping stone, aggregate, or a field specimen; this ordinary pebble has little jewelry value.

Geological facts

The smooth triangular form and surface rounding indicate transport by water or abrasion. Brown bands are probably iron-oxide-rich cement or staining rather than distinct mineral veins.

Field identification & locations

Identify it by visible sand grains, granular texture, rounded edges, and weakly gritty surfaces; dilute hydrochloric acid may fizz only if carbonate cement is present. Common worldwide, especially in streambeds, beaches, and weathered sandstone terrains.