sedimentary

Sandstone

Arenite (SiO2 dominant)

Hardness: 6-7 Mohs; Color: Tan, brown, or grayish; Luster: Dull or earthy; Crystal structure: Clastic (sand-sized grains); Cleavage: None; Specific gravity: 2.2-2.8

Hardness: 6-7 Mohs
Color: Tan, brown, or grayish
Luster: Dull or earthy

Identified June 25, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Tan, brown, or grayish; Luster: Dull or earthy; Crystal structure: Clastic (sand-sized grains); Cleavage: None; Specific gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments, typically in river beds, deserts, or coastal environments. This specimen appears water-worn, likely from a fluvial or glacial deposit.

Uses & applications

Used in construction, as a building stone, for grindstones, or as a reservoir for oil and natural gas in geological formations. Often used in landscaping.

Geological facts

Sandstone represents about 20% of all sedimentary rocks on Earth and is critical for containing groundwater in aquifers. The presence of iron oxides often gives it a reddish or brownish hue.

Field identification & locations

Identify by its 'sandpaper' feel and visible grain structure. It is commonly found in sedimentary basins and riverbeds. For collectors, look for cross-bedding or fossil inclusions.