Sandstone

Physical Properties

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

Formation & Geological History

Formed from the accumulation and cementation of sand-sized mineral grains or rock fragments (clasts) in environments such as deserts, riverbeds, or ocean floors over millions of years.

Uses & Applications

Extensively used as a building material, paving stone, and decorative gravel. It is also an important reservoir rock for groundwater and petroleum.

Geological Facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. Famous landmarks like the Grand Canyon exhibit massive layers of diverse sandstone formations.

Field Identification & Locations

Identify in the field by its 'gritty' feel, similar to sandpaper, and visible grains. Common in sedimentary basins and arid regions. Collectors look for unique banding or fossils within the layers.

Identified on: 4/14/2026

Mode: Standard