sedimentary

Sandstone

Quartz-rich clastic sandstone, likely arkose or subarkose

AI-generated identification · may be incorrect

Usually Mohs 6–7 because of quartz; tan to reddish, dull to slightly gritty, with visible sand-sized grains and porous texture. Composed mainly of quartz, feldspar, and rock fragments, commonly cemented by silica, calcite, or iron oxides.

Identified August 28, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when sand accumulates, is compacted, and cemented in rivers, deserts, beaches, or shallow marine settings. Its exact geological age cannot be determined from the image; sandstone ranges from Precambrian to modern.

Uses & applications

Used as building stone, paving, wall material, aggregate, and occasionally ornamental stone. Common varieties are collected as landscape or educational specimens rather than gemstones.

Geological facts

The angular, granular surface and tan color are characteristic of weathered sandstone; iron-oxide cement can produce buff, orange, or red hues.

Field identification & locations

Common worldwide, including the Colorado Plateau, western United States, India, Australia, and Europe. Identify it by sand-sized grains that feel abrasive and may shed under weathering; acid testing is usually negative unless calcite cement is present.