sedimentary

Sandstone (Red Sandstone)

Arenite (SiO2 based with Fe2O3 staining)

Hardness: 6-7 (Mohs scale), Color: Red, reddish-brown, or orange due to iron oxide (hematite) coating. Luster: Dull to earthy. Crystal structure: Clastic texture with visible sand grains. Cleavage: None. Specific Gravity: 2.2 - 2.8.

Luster: Dull to earthy

Identified June 30, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments. The red color suggests deposition in an oxidizing environment, such as a desert or river floodplain. These are often of Paleozoic or Mesozoic age.

Uses & applications

Commonly used as a building material, decorative stone, for domestic flagstones, and in the manufacturing of glass or grinding stones.

Geological facts

Red sandstone is a major component of iconic landforms like the Grand Canyon and the 'Red Rocks' of Sedona, Arizona. It provides significant insights into ancient wind patterns and sea level changes.

Field identification & locations

Identify in the field by its gritty texture (feels like sandpaper) and visible layers or cross-bedding. Commonly found in arid regions, coastal areas, and near ancient riverbeds. To confirm, check if it scratches glass (indicating quartz content).

Other sedimentary specimens

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Sandstone or Siltstone

Arenite (if sandstone)

Sedimentary

Cone-in-cone structure (Limestone)

Cone-in-cone structure (Secondary Sedimentary Structure)

sedimentary

Chert Breccia

Brecciated Chert (Microcrystalline Silica)

sedimentary

Sandstone Grain

Clastic Sedimentary Rock Grain (SiO2 dominated)

sedimentary

Shale or Slaty Mudstone

Argillaceous sedimentary rock

sedimentary

Sandstone

Arenite (primarily SiO2)

sedimentary