sedimentary

Sandstone

Arenite (primarily SiO2)

Hardness: 6-7 (Mohs scale); Color: tan, white, yellow, or grey; Luster: dull/earthy; Crystal structure: granular clastic; Cleavage: none; Specific gravity: 2.2-2.8

Hardness: 6-7 (Mohs scale)
Color: tan, white, yellow, or grey
Luster: dull/earthy

Identified March 22, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: tan, white, yellow, or grey; Luster: dull/earthy; Crystal structure: granular clastic; Cleavage: none; Specific gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of mineral particles or rock fragments (sand) over millions of years. This specimen displays a typical clastic texture formed in high-energy depositional environments like riverbeds or coastal dunes.

Uses & applications

Commonly used as a building material, in the manufacture of glass (if high silica), as a source of abrasive material, and as a decorative stone in landscaping.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. Old Red Sandstone, found in the British Isles, dates back to the Devonian period and served as a key piece of evidence for early geologists like James Hutton.

Field identification & locations

Identify in the field by its gritty, sandpaper-like feel and visible grains. It is commonly found in sedimentary basins and arid regions globally. Collectors should look for distinct layering (cross-bedding) or fossils.