Ferruginous Sandstone

Physical Properties

Hardness: 6-7 (Mohs scale) for quartz grains; Color: Brick red to brownish-red; Luster: Dull or earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.2-2.8

Formation & Geological History

Formed through the accumulation of sand-sized grains (mostly quartz) cemented by iron oxides like hematite or goethite. Often formed in arid environments or river deltas.

Uses & Applications

Used primarily as decorative building stone, in masonry, or as a source of iron ore if concentration is high enough. Commonly used as landscaping rock.

Geological Facts

The red color of many famous geological formations, such as those in Sedona, Arizona or the Red Rocks in Colorado, is due to the presence of iron oxide (rust) in sandstone.

Field Identification & Locations

Identified by its gritty sandpaper-like texture and deep red coloration. Can be found in many terrestrial sedimentary basins worldwide. It often forms prominent cliffs due to its durability.

Identified on: 4/28/2026

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