sedimentary

Sandstone

Arenite (primarily Quartz and Feldspar composition)

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs scale); Color: Brown, tan, reddish-brown; Luster: Dull/Earthy; Structure: Clastic, granular texture; Cleavage: None (fractures across grains); Specific Gravity: 2.2-2.8

Hardness: 6-7 (Mohs scale)
Color: Brown, tan, reddish-brown
Luster: Dull/Earthy

Identified July 21, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Brown, tan, reddish-brown; Luster: Dull/Earthy; Structure: Clastic, granular texture; Cleavage: None (fractures across grains); Specific Gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments over millions of years. This specimen appears weathered/rounded, likely by fluvial (river) or coastal water movement.

Uses & applications

Commonly used as a building material, in decorative masonry, as a reservoir rock for petroleum and groundwater, and as a source of silica for glassmaking.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. The famous Red Rocks Amphitheatre in Colorado and the Treasury at Petra are both carved into sandstone formations.

Field identification & locations

Identify in the field by its gritty, sandpaper-like feel. Often found in desert environments, river beds, and coastal outcrops. Use a magnifying glass to see the individual rounded sand grains.