sedimentary
Ferruginous Sandstone with Quartz Inclusions
Clastic Sedimentary Rock (Iron-rich Sandstone)
Hardness: 6-7 (on Mohs scale for quartz grains); Color: Reddish-brown, rust, beige; Luster: Gritty, dull to vitreous where quartz is present; Structure: Granular/Clastic; Cleavage: None (conchoidal fracture on quartz inclusions); Specific Gravity: 2.6-2.8
- Hardness
- 6-7 (on Mohs scale for quartz grains)
- Color
- Reddish-brown, rust, beige
- Luster
- Gritty, dull to vitreous where quartz is present
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (on Mohs scale for quartz grains); Color: Reddish-brown, rust, beige; Luster: Gritty, dull to vitreous where quartz is present; Structure: Granular/Clastic; Cleavage: None (conchoidal fracture on quartz inclusions); Specific Gravity: 2.6-2.8
Formation & geological history
Formed through the weathering, transport, and deposition of sand-sized grains, primarily quartz, which are then lithified. The reddish color is due to the presence of iron oxides (hematite or limonite) acting as a cement or coating. This specimen likely dates from the Paleozoic to Mesozoic era depending on the specific basin of origin.
Uses & applications
Used primarily in construction as a building stone or road aggregate. Some iron-rich sandstones are studied as low-grade iron ores. In landscaping, it is valued for its earthy, natural aesthetic.
Geological facts
The red color in these rocks is often referred to as 'red beds,' which are significant because they indicate the presence of oxygen in the atmosphere at the time of deposition. Sandstone makes up about 20% of all sedimentary rocks on Earth.
Field identification & locations
Identify in the field by its gritty texture (feels like sandpaper) and visible quartz grains embedded in a rusty matrix. Commonly found in desert environments, river basins, and coastal areas. Collectors should look for unique banding or larger inclusion crystals.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
sedimentary