sedimentary

Ferruginous Sandstone

Arenite with limonite/goethite cement

AI-generated identification · may be incorrect

Hardness: 6-7 (individual quartz grains), 2-3 (iron oxide matrix); Color: yellow, ochre, rusty brown; Luster: dull, earthy; Crystal structure: granular clastic texture; Specific gravity: 2.2-2.8

Hardness: 6-7 (individual quartz grains), 2-3 (iron oxide matrix)
Color: yellow, ochre, rusty brown
Luster: dull, earthy

Identified June 26, 2026More sedimentary →

Explore Ferruginous Sandstone in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 6-7 (individual quartz grains), 2-3 (iron oxide matrix); Color: yellow, ochre, rusty brown; Luster: dull, earthy; Crystal structure: granular clastic texture; Specific gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation of sand-sized minerals, mostly quartz, which are then cemented together by iron oxides (limonite or goethite) precipitated from groundwater. Commonly found in riverbeds, deltas, and arid basins.

Uses & applications

Historically used as a low-grade building stone and a pigment (ochre); occasionally used in landscaping or as a source of iron ore in primitive metallurgy.

Geological facts

The distinct yellow color is due to the presence of hydrated iron oxides. In some areas, these stones are referred to as 'ironstone' or 'yellow dog' in local vernacular.

Field identification & locations

Identified by its gritty, sand-paper like feel and its tendency to leave a yellowish streak on a streak plate. It is common in regions with heavily oxidized soil profiles.