sedimentary

Sandstone (with Iron Staining)

Arenite (composed primarily of SiO2 with Fe2O3 staining)

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs); Color: Tan, reddish-brown, or ochre; Luster: Dull/Earthy; Crystal structure: Clastic (granular); Cleavage: None; Specific Gravity: 2.2-2.8

Hardness: 6-7 (Mohs)
Color: Tan, reddish-brown, or ochre
Luster: Dull/Earthy

Identified April 4, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs); Color: Tan, reddish-brown, or ochre; Luster: Dull/Earthy; Crystal structure: Clastic (granular); Cleavage: None; Specific Gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of mineral particles or rock fragments (clasts) the size of sand. These typically form in river beds, deserts, or coastal environments. This specimen shows significant iron oxide staining, suggesting exposure to oxygen and water during or after lithification.

Uses & applications

Used widely as a building material, in the manufacturing of glass (if high silica content), and as an abrasive. Ground sandstone is also used in the petroleum industry for hydraulic fracturing.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. Famous geological formations like the Grand Canyon and Petra are primarily composed of sandstone. It is highly porous and often serves as a natural aquifer for groundwater.

Field identification & locations

Identify in the field by its gritty 'sandpaper' texture. If you rub your thumb across it, small grains of sand may displace. It is commonly found in sedimentary basins worldwide. For collectors, look for unique weathering patterns or fossil inclusions.