sedimentary

Weathered sandstone fragment

Quartz-rich sandstone, likely ferruginous sandstone

AI-generated identification · may be incorrect

Tan to brown, dull earthy luster, visibly granular texture, and no obvious cleavage; typically Mohs hardness 6–7 for quartz grains, with specific gravity around 2.2–2.7. The rounded shape and darker surface suggest weathering or iron-oxide staining.

Identified September 21, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand-sized mineral grains—mostly quartz, commonly with feldspar and iron-oxide cement—were compacted and cemented in ancient rivers, beaches, dunes, or shallow seas. Its precise geological age cannot be determined from the photograph.

Uses & applications

Used as building and paving stone, aggregate, and occasionally as a decorative material; this small fragment has little practical use. Common specimens generally have negligible collector value.

Geological facts

Sandstone often preserves ripple marks, cross-bedding, fossils, or iron-stained layers. The dark brown coating may be limonite or weathering varnish rather than the rock’s original color.

Field identification & locations

Common worldwide, especially in sedimentary basins, cliffs, riverbeds, and construction fill. Identify it by rubbing or breaking a fresh surface to reveal gritty quartz grains; acid reaction is usually absent unless carbonate cement is present.