sedimentary

Sandstone

Arenite (primarily SiO2 - Silicon Dioxide)

Hardness: 6-7 Mohs scale. Color: Tan, brown, or light yellow with visible oxidation. Luster: Dull/Earthy. Structure: Clastic, composed of sand-sized mineral grains or rock fragments. Specific Gravity: 2.2–2.8.

Hardness: 6-7 Mohs scale
Color: Tan, brown, or light yellow with visible oxidation
Luster: Dull/Earthy

Identified January 30, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation and subsequent lithification of sand-sized mineral particles, most commonly quartz. This specimen appears and shows signs of being water-worn or weathered. These can form over millions of years in riverbeds, deserts, or coastal environments.

Uses & applications

Widely used in the construction industry as building stone or crushed for aggregate. It is also used as an abrasive in grinding wheels and as a historical medium for sculpture and architecture.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. It is highly porous and often serves as an important aquifer for groundwater or a reservoir for oil and natural gas.

Field identification & locations

Identify in the field by its gritty texture (feels like sandpaper) and visible layering if present. Frequently found in outcrops, riverbanks, or as field stones. Collectors should look for unique cross-bedding patterns or fossils embedded within the matrix.

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