sedimentary

Sandstone

Arenite (composed primarily of SiO2)

Hardness: 6-7 on Mohs scale; Color: Tan, brown, or earthy yellow (due to iron oxides); Luster: Dull or earthy; Crystal structure: Clastic (grainy texture); Cleavage: None (grains are cemented together); Specific gravity: 2.2-2.8

Hardness: 6-7 on Mohs scale
Color: Tan, brown, or earthy yellow (due to iron oxides)
Luster: Dull or earthy

Identified March 22, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation and cementation of sand-sized grains (mostly quartz and feldspar) in environments such as river beds, deserts, or marine basins. This sample appears to be from a terrestrial weathering environment.

Uses & applications

Commonly used as a building material, paving stone, and in the production of glass (if high purity quartz). It is also a significant reservoir rock for groundwater and petroleum.

Geological facts

Sandstone makes up about 20-25% of all sedimentary rocks on Earth. The famous red rocks of the Grand Canyon and Petra in Jordan are primarily made of sandstone.

Field identification & locations

Identify in the field by its gritty texture (feels like sandpaper) and visible layering (bedding). It can often be scratched with a steel blade if the cement is weak, but the grains themselves are hard quartz. Found globally in basins and mountainous regions.