sedimentary

Sandstone

Arenite (SiO2 based)

Hardness: 6-7 Mohs; Color: Brown, tan, and dark grey; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None/Irregular fracture; Specific gravity: 2.2-2.8

Hardness: 6-7 Mohs
Color: Brown, tan, and dark grey
Luster: Dull/Earthy

Identified May 14, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Brown, tan, and dark grey; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None/Irregular fracture; Specific gravity: 2.2-2.8

Formation & geological history

Formed by the accumulation and lithification of sand-sized mineral grains or rock fragments, typically in river beds, beaches, or deserts. This specimen shows signs of iron oxide staining and potential secondary mineralization.

Uses & applications

Used extensively in construction as building stone, pavers, and crushed stone; historically used for grindstones and in glass manufacturing if high in silica.

Geological facts

Sandstone represents about 20% of all sedimentary rocks on Earth. It acts as a major reservoir for groundwater and petroleum due to its high porosity and permeability.

Field identification & locations

Identify in the field by its gritty 'sandpaper' texture and visible mineral grains. Commonly found in sedimentary basins and exposed canyon walls. Use a magnifying glass to see the individual cemented grains.