sedimentary

Sandstone

Arenite (primarily SiO2)

Hardness: 6-7 (Mohs scale); Color: Brownish-red to tan; Luster: Dull/Earthy; Crystal structure: Clastic (sand grains); Cleavage: None; Specific gravity: 2.2 - 2.8.

Hardness: 6-7 (Mohs scale)
Color: Brownish-red to tan
Luster: Dull/Earthy

Identified March 29, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Brownish-red to tan; Luster: Dull/Earthy; Crystal structure: Clastic (sand grains); Cleavage: None; Specific gravity: 2.2 - 2.8.

Formation & geological history

Formed from the accumulation and cementation of mineral particles or rock fragments (0.0625 to 2 mm size), typically in riverbeds, deserts, or marine environments. Age varies from Precambrian to Holocene.

Uses & applications

Commonly used in construction for building stone, pavers, and crushing for glass manufacturing. In collecting, it is valued for its texture and potential fossil content.

Geological facts

Sandstone makes up about 20-25% of all sedimentary rocks on Earth. The famous 'Red Rocks' of the American Southwest are composed of layered sandstone colored by iron oxide.

Field identification & locations

Identify in the field by its gritty, sandpaper-like feel. It is found globally in sedimentary basins. Collectors should look for unique layering (cross-bedding) or inclusions of other minerals.