sedimentary

Sandstone

Arenite (primarily Quartz-based)

Hardness: 6-7 (Mohs scale); Color: Tan, brown, and reddish-purple (due to iron oxides); Luster: Dull/Earthy; Texture: Granular and gritty like sandpaper; Structure: Clastic.

Hardness: 6-7 (Mohs scale)
Color: Tan, brown, and reddish-purple (due to iron oxides)
Luster: Dull/Earthy

Identified July 12, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Tan, brown, and reddish-purple (due to iron oxides); Luster: Dull/Earthy; Texture: Granular and gritty like sandpaper; Structure: Clastic.

Formation & geological history

Formed through the accumulation and cementation of mineral particles or rock fragments (sand) over millions of years, typically in desert, river, or ocean environments. This specimen shows distinct bedding or oxidation layers.

Uses & applications

Commonly used in construction, paving, landscaping, and as a material for grindstones. It is also a significant reservoir rock for oil and groundwater.

Geological facts

Sandstone makes up about 20-25% of all sedimentary rocks on Earth. The color variations, like the purple and tan seen here, are often the result of iron oxidation occurring at different rates or under different chemical conditions.

Field identification & locations

Identify by its 'sandpaper' feel and visible grains. It is extremely common in arid regions and canyonlands. Collectors look for unique banding patterns known as 'Liesegang rings' or 'Picture Sandstone'.