sedimentary

Rounded iron-stained sandstone pebble

Quartz-rich sandstone, commonly ferruginous sandstone (SiO₂-dominated)

AI-generated identification · may be incorrect

Typically Mohs hardness 6–7 for quartz grains, with a dull to earthy, slightly gritty surface; tan-orange color comes from iron-oxide cement. Usually clastic and non-crystalline overall, with no obvious cleavage; density is commonly about 2.2–2.6 g/cm³.

Identified August 26, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand-sized quartz and rock fragments were deposited, compacted, and cemented, then rounded by stream or shoreline abrasion. Its exact geological age cannot be determined from the photograph; sandstone ranges from Precambrian to recent.

Uses & applications

Common sandstone is used as building stone, paving, aggregate, and occasionally decorative material. This small rounded piece has mainly educational or modest collecting value.

Geological facts

The orange coloration most often reflects hematite or goethite coatings between quartz grains. A streak or freshly broken surface can reveal whether the color is a surface stain or intrinsic cement.

Field identification & locations

Likely identifiable by its uniform gritty texture, rounded shape, and weak response to dilute acid; quartz-rich sandstone generally does not fizz. Common in riverbeds, beaches, deserts, and eroding sedimentary formations; a hand lens helps reveal sand grains.