sedimentary

Weathered iron-rich sandstone or ironstone

Ferruginous sandstone, commonly quartz-rich with iron oxides (Fe₂O₃/FeOOH)

AI-generated identification · may be incorrect

Hardness about 6–7 for quartz grains, but the weathered surface may crumble; reddish-brown, dull to earthy luster, granular texture, and no obvious cleavage. The pale branching surface markings may be mineral veins, weathering rinds, or lichen rather than crystals.

Identified August 9, 2026More sedimentary →

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Physical properties

Formation & geological history

A sedimentary rock formed when sand was deposited, compacted, and cemented, with later groundwater adding hematite or goethite cement; the exact geological age cannot be determined from the image. Oxidation during weathering produces the red-brown coloration.

Uses & applications

Used locally as building stone, aggregate, and occasionally decorative stone; ordinary specimens generally have little commercial or collector value.

Geological facts

Iron oxides can strongly stain the fingers and give sandstone a rusty red color. A streak test and acid test are more diagnostic than color alone.

Field identification & locations

Common in continental sandstones and weathered ironstone deposits worldwide. Look for visible sand grains, gritty texture, red-brown iron staining, and weak reaction to dilute hydrochloric acid; distinguish from basalt by its granular, layered or friable character.