sedimentary

Sandstone

Arenite (composed primarily of SiO2)

Hardness: 6-7 Mohs; Color: Tan, brown, or buff; Luster: Dull/Earthy; Structure: Clastic with visible sand-sized grains; Specific Gravity: 2.2-2.8

Hardness: 6-7 Mohs
Color: Tan, brown, or buff
Luster: Dull/Earthy

Identified March 31, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Tan, brown, or buff; Luster: Dull/Earthy; Structure: Clastic with visible sand-sized grains; Specific Gravity: 2.2-2.8

Formation & geological history

Formed from the accumulation and cementation of mineral particles or rock fragments (detritus) like quartz or feldspar. This process (lithification) typically occurs in river beds, deserts, or marine environments over millions of years.

Uses & applications

Major use in construction as dimension stone for walls, paving, and decorative facades. Crushed sandstone is used in road base and glass manufacturing.

Geological facts

Sandstone can be a significant reservoir for groundwater (aquifers) and oil/gas due to its porosity. Famous examples include the red rock formations of the American Southwest and the ancient city of Petra.

Field identification & locations

Identify by a gritty 'sandpaper' feel and visible layers (bedding). It is found worldwide in sedimentary basins. Collectors often look for examples with distinct cross-bedding or fossil inclusions.