Sandstone

Clastic sedimentary rock (primarily SiO2)

Rock Type: sedimentary

Sandstone

Physical Properties

Hardness: 6-7 (Mohs); Color: Tan, yellow, or buff; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific gravity: 2.2-2.8. Feels like sandpaper.

Formation & Geological History

Formed through the accumulation of sand-sized mineral particles or rock fragments, which are then lithified (turned to rock) by pressure and mineral cement. These often form in deserts, riverbeds, and beaches over millions of years.

Uses & Applications

Extensively used as a building material, in the manufacturing of glass and concrete, as a decorative stone in landscaping, and as a reservoir rock in the petroleum industry.

Geological Facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. The famous red rock formations of the American Southwest, such as those in Zion National Park, are composed of sandstone.

Field Identification & Locations

Identify by its gritty texture (feels like sandpaper) and visible sand grains. These specimens appear to be weathered fieldstones. Commonly found in coastal or formerly aquatic regions.

Identified on: 4/26/2026

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