sedimentary

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 staining)

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs scale); Color: Tan, brown, and yellowish-orange due to iron oxides; Luster: Dull/Earthy; Crystal structure: Granular (clastic); Cleavage: None; Specific gravity: 2.2-2.8

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

Identified March 21, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Tan, brown, and yellowish-orange due to iron oxides; Luster: Dull/Earthy; Crystal structure: Granular (clastic); Cleavage: None; Specific gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation, compaction, and cementation of sand-sized mineral grains or rock fragments. The visible yellow-orange staining suggests a secondary formation process involving the oxidation of iron-rich minerals (limonite/hematite) by groundwater.

Uses & applications

Commonly used as a building material, paving stone, and in the production of glass (if high quartz content). Decorative specimens are used in landscaping.

Geological facts

Sandstone accounts for about 20% of all sedimentary rocks on Earth. The 'rust' coloring seen on this specimen is identical to the process that creates the famous red rock formations in places like Sedona, Arizona, or the Grand Canyon.

Field identification & locations

Identify in the field by its gritty, sandpaper-like feel and visible layered or blocky fracturing. Common in riverbeds, deserts, and mountain outcrops. Look for 'bedding planes' where the rock naturally splits.