sedimentary

Red sandstone fragment

Quartz-rich sandstone, likely ferruginous sandstone (SiO₂ with iron-oxide cement)

AI-generated identification · may be incorrect

Typically Mohs hardness 6–7 for quartz grains, but friable overall; reddish-orange color, dull to weakly earthy luster, visible fine sand grains and thin lamination. No obvious cleavage; porosity and rough fracture are common.

Identified September 13, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand-sized quartz and feldspar grains were compacted and cemented, with iron oxides producing the red color; age cannot be determined from the photograph. Common in ancient river, dune, floodplain, and shallow-marine sedimentary formations.

Uses & applications

Used as building stone, paving, landscaping aggregate, and a source of silica; attractive pieces may be collected or used decoratively, but this small fragment has little commercial value.

Geological facts

The red coloration generally comes from hematite or related iron-oxide coatings, not from red quartz itself. Fine parallel layers suggest deposition in changing currents or wind conditions.

Field identification & locations

Identify it by gritty texture, layered sedimentary fabric, earthy red color, and a glass scratch test on individual grains; it should not fizz in dilute hydrochloric acid unless carbonate cement is present. Common worldwide, especially in arid and continental basins.