sedimentary

Weathered sandstone cobble

Quartz-rich sandstone, likely arkosic or ferruginous sandstone

AI-generated identification · may be incorrect

Predominantly pale tan, fine- to medium-grained, porous, and matte with rounded weathering surfaces; mainly quartz with possible feldspar, clay minerals, and iron oxides. Likely Mohs hardness 6–7 for grains but relatively friable overall; no visible cleavage or crystals.

Identified September 5, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand was deposited, compacted, and cemented, then rounded and smoothed by abrasion and weathering. Its exact geological age cannot be determined from the image; sandstone ranges from Precambrian to modern formations.

Uses & applications

Used as building stone, paving, landscaping material, and aggregate; attractive pieces may be collected as natural curiosities. It has little gemstone value.

Geological facts

The large smooth form and shallow cavities suggest prolonged stream, beach, or wave abrasion, though wind and chemical weathering may also contribute.

Field identification & locations

Identify sandstone by visible gritty texture, porous surfaces, and scratching glass with individual quartz grains while the whole piece may crumble. Common worldwide, especially in sedimentary basins, riverbeds, beaches, and desert regions.