sedimentary

Sandstone

Arenite (CaCO3/SiO2 cemented quartz)

Hardness: 6-7 (Mohs scale); Color: Tan, brown, or grey with weathered patina; Luster: Dull to earthy; Crystal structure: Clastic (grains); Cleavage: None, breaks across grains.

Hardness: 6-7 (Mohs scale)
Color: Tan, brown, or grey with weathered patina
Luster: Dull to earthy

Identified June 19, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Tan, brown, or grey with weathered patina; Luster: Dull to earthy; Crystal structure: Clastic (grains); Cleavage: None, breaks across grains.

Formation & geological history

Formed by the accumulation and cementation of mineral particles or rock fragments (clasts) usually quartz or feldspar. It originates from deposit environments like beaches, deserts, or river deltas and undergoes lithification over millions of years.

Uses & applications

Commonly used as a construction material for paving stones, landscaping, and decorative flagstone. Historically significant in cathedrals and monuments due to its workability.

Geological facts

Sandstone can act as an aquifer for groundwater or a reservoir for petroleum and natural gas due to its porosity. It often preserves fossils and ripple marks from ancient water currents.

Field identification & locations

Identified in the field by its gritty, sandpaper-like texture and visible bedding planes. Found globally in sedimentary basins. Collectors often look for iron-oxide staining or unique 'picture' patterns.