sedimentary

Sandstone (Arkose)

Arkose Sandstone (SiO2 with KAlSi3O8)

AI-generated identification · may be incorrect

Hardness: 6-7 Mohs; Color: Pinkish-red, tan, or brown; Luster: Dull to earthy; Texture: Coarse-grained, clastic; Components: High feldspar content (>25%) and quartz.

Hardness: 6-7 Mohs
Color: Pinkish-red, tan, or brown
Luster: Dull to earthy

Identified June 28, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Pinkish-red, tan, or brown; Luster: Dull to earthy; Texture: Coarse-grained, clastic; Components: High feldspar content (>25%) and quartz.

Formation & geological history

Formed from the rapid weathering and deposition of feldspar-rich igneous or metamorphic rocks (like granite). It typically accumulates in alluvial fans or rift basins where transport distance is short.

Uses & applications

Used as a construction material, building stone, and road aggregate. Historically used for millstones and in some architectural masonry.

Geological facts

Arkose is often called 'dirty sandstone' because of its mineral variety. It is a key indicator for geologists that the sediment source was close by and the climate was likely dry.

Field identification & locations

Identify by its rough, sandpaper-like feel and visible pinkish feldspar grains. Commonly found in sedimentary basins near granitic mountain ranges. Look for quartz and angular grains.