sedimentary
Ferruginous Sandstone (ironstone)
Sandstone with iron oxide cement (limonite/hematite)
Hardness: 6-7 (quartz grains); Color: Reddish-brown to rusty orange; Luster: Dull, earthy; Crystal structure: Granular bedding; Specific Gravity: 2.2-2.8.
- Hardness
- 6-7 (quartz grains)
- Color
- Reddish-brown to rusty orange
- Luster
- Dull, earthy
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (quartz grains); Color: Reddish-brown to rusty orange; Luster: Dull, earthy; Crystal structure: Granular bedding; Specific Gravity: 2.2-2.8.
Formation & geological history
Formed by the deposition of quartz sand in terrestrial or near-shore environments where iron-rich groundwater or oxygenated water precipitates iron oxides as a cementing agent. Common in Phanerozoic strata.
Uses & applications
Used as a building stone (historically), a minor source of iron ore in some regions, and as decorative rock in landscaping.
Geological facts
The red color is caused by the oxidation of iron, literally the same process as rusting metal. Large formations of this stone create the famous red landscapes of the American Southwest.
Field identification & locations
Identify by the sandy texture that feels like sandpaper and the characteristic dark red or chocolate brown color that leaves a trail if rubbed against harder stones. Commonly found in desert regions or eroded riverbeds.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite
sedimentary