sedimentary

Weathered sandstone

Quartz–feldspar arenite, commonly ferruginous sandstone

AI-generated identification · may be incorrect

Typically fine- to medium-grained, tan to brown, with a rough granular texture and dull to earthy luster; composed mainly of quartz and feldspar cemented by silica, calcite, or iron oxides. Hardness is variable (about 6–7 for grains, lower overall), with no cleavage and specific gravity around 2.2–2.7.

Identified August 27, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand accumulated, compacted, and cemented in rivers, deserts, beaches, or shallow seas; iron-oxide weathering produces the brown coloration. Its exact geological age cannot be determined from the image and may range from Precambrian to Recent.

Uses & applications

Used as building stone, paving, wall stone, aggregate, and occasionally as a decorative material; porous varieties may serve as groundwater or petroleum reservoirs.

Geological facts

Common field clues are visible sand grains, gritty texture, layered or cross-bedded surfaces, and color variation from iron staining. It commonly occurs in sedimentary basins worldwide; dilute acid may fizz if calcite-cemented.

Field identification & locations

Likely a common weathered fragment rather than a collectible specimen; confirm with a hand lens, grain-size inspection, and scratch testing. Typical value is $1–$10 for a loose fragment, or $10–$50 for attractive specimens.