sedimentary

Red sandstone fragment

Ferruginous sandstone, composed mainly of quartz (SiO₂) with iron-oxide cement

AI-generated identification · may be incorrect

Typically Mohs hardness 6–7 for quartz grains, though the rock crumbles more easily; reddish-orange, dull to earthy luster, porous, and usually fine- to medium-grained with no cleavage. The visible rounded, weathered surface is consistent with sandstone, but a photo cannot confirm composition.

Identified August 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when sand accumulates, compacts, and cements in rivers, deserts, beaches, or shallow marine settings; iron oxides produce the red color. Its age could range from relatively young to hundreds of millions of years, depending on locality.

Uses & applications

Used as building stone, paving, aggregate, and occasionally decorative material; this small ordinary fragment has negligible commercial use.

Geological facts

The red coloration commonly comes from hematite or limonite coatings around quartz grains. Sandstone can preserve ripple marks, cross-bedding, fossils, and ancient environmental clues.

Field identification & locations

Look for visible sand grains, gritty texture, layered bedding, and reddish iron staining; a steel nail usually does not scratch quartz grains, though it may gouge the cement. Common worldwide, especially in arid and sedimentary-basin regions.