Sandstone (Quartzose)

Physical Properties

Hardness: 6-7 (Mohs); Color: Tan, brown, or buff; Luster: Dull/Earthy; Crystal structure: Clastic (sand-sized grains); Cleavage: None (orthoquartzite fragmenting); Specific gravity: 2.3-2.4

Formation & Geological History

Formed from the accumulation and cementation of sand-sized mineral particles or rock fragments. This specific rounded shape indicates fluvial or glacial erosion where the rock was tumbled in water over long periods.

Uses & Applications

Common sandstone is used in construction (building stone, flagstone), as an abrasive, or crushed for concrete aggregate. Worn river stones are popular for landscaping.

Geological Facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. Because of its porosity, it is an important aquifer for groundwater and a reservoir for petroleum.

Field Identification & Locations

Identify by its gritty texture (feels like sandpaper) and visible grains. Often found in riverbeds, canyons, and dry washes. Commonly found globally wherever ancient sedimentary basins exist.

Identified on: 4/25/2026

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