sedimentary

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2 with Fe2O3 oxides)

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs scale); Color: Brown, tan, reddish-orange; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific gravity: 2.2-2.8

Hardness: 6-7 (Mohs scale)
Color: Brown, tan, reddish-orange
Luster: Dull/Earthy

Identified March 25, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Brown, tan, reddish-orange; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of mineral particles or rock fragments (detritus) such as sand. This specimen shows oxidation (rusting) of iron minerals, likely formed in a terrestrial or shallow marine environment over millions of years.

Uses & applications

Commonly used as a building material, paving stone, and in the production of glass. It is also a primary reservoir rock for oil, gas, and groundwater.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. The distinct reddish-brown 'desert' colors often seen in the American Southwest are due to the same iron-oxide staining present on this specimen.

Field identification & locations

Identify by its gritty, sand-like texture when rubbed. It is globally ubiquitous, found in many riverbeds and canyons. Collectors value specimens with unique weathering patterns or fossil inclusions.