sedimentary

Red sandstone boulder

Quartz-rich sandstone, commonly arkose or iron-oxide-cemented sandstone

AI-generated identification · may be incorrect

Typically Mohs hardness 6–7 for quartz grains, reddish to pink, and dull to slightly gritty; clastic grains are cemented by silica, calcite, or iron oxides. The specimen appears massive and weathered, with no obvious cleavage or visible crystals.

Identified August 16, 2026More sedimentary →

Explore Red sandstone boulder in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed when sand accumulated in ancient rivers, dunes, or floodplains and lithified by burial and cementation; its red color reflects oxidized iron minerals. Exact age and formation basin cannot be determined from the image.

Uses & applications

Used as building stone, paving, wall stone, aggregate, and landscaping material; attractive fine-grained pieces may be decorative, but this boulder has little gem value.

Geological facts

Red sandstone commonly records arid terrestrial environments and can preserve cross-bedding, ripple marks, or fossils. Its color is usually caused by hematite coatings on quartz and feldspar grains.

Field identification & locations

Identify it by its granular texture, blocky weathering, reddish iron staining, and lack of glassy crystals; a hand lens and acid test can help distinguish sandstone from volcanic rock or limestone. Common worldwide, especially in deserts and sedimentary basins.