sedimentary

Ferruginous Sandstone

Sandstone (SiO2 with Fe2O3 cement)

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs); Color: Reddish-brown, tan, or rust; Luster: Dull to earthy; Texture: Fine to medium-grained; Cleavage: None; Specific Gravity: 2.3-2.6

Hardness: 6-7 (Mohs)
Color: Reddish-brown, tan, or rust
Luster: Dull to earthy

Identified July 18, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs); Color: Reddish-brown, tan, or rust; Luster: Dull to earthy; Texture: Fine to medium-grained; Cleavage: None; Specific Gravity: 2.3-2.6

Formation & geological history

Formed from the accumulation and cementation of sand-sized grains (mostly quartz) in high-energy environments like rivers or beaches. The reddish color comes from iron oxide (hematite) acting as a cement between grains.

Uses & applications

Commonly used in construction as building stone, pavers, or crushed aggregate. Historically used for making grinding tools or simple artifacts.

Geological facts

Sandstone covers a significant portion of the Earth's crust and is a primary reservoir for underground water and petroleum. This specific rounded shape suggests long-term erosion in a high-energy water system like a riverbed or coastal zone.

Field identification & locations

Identify by its gritty texture (feels like sandpaper) and visible grains. It is extremely common in sedimentary basins worldwide. For collectors, look for uniform rounding and consistent iron staining.