sedimentary

Iron-rich sandstone (ferruginous sandstone)

Quartz-rich sandstone cemented by iron oxides, chiefly hematite (Fe₂O₃) and/or goethite (FeO(OH))

AI-generated identification · may be incorrect

Typically fine- to medium-grained, reddish-brown, gray, and metallic-looking where iron-rich; quartz has Mohs hardness 7, while iron-oxide coatings are softer (about 5–6), with earthy to weakly silky luster and no consistent cleavage.…

Identified September 9, 2026More sedimentary →

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At a glance

Common name: Iron-rich sandstone (ferruginous sandstone)
Scientific name: Quartz-rich sandstone cemented by iron oxides, chiefly hematite (Fe₂O₃) and/or goethite (FeO(OH))
Category: sedimentary
Identified: September 9, 2026
Method: Standard

AI Estimated Value

About $2–$15 for a small common specimen; $20–$50 if unusually attractive, labeled, or from a notable locality.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Formed when sand accumulated in a depositional basin and was lithified, then stained or cemented by oxidized iron-bearing groundwater. Its precise age cannot be determined from the image; ferruginous sandstones occur from Precambrian to Recent strata.

Uses & applications

Used locally as building or landscaping stone and as a minor iron resource; attractive pieces are collected as geological specimens. It is generally not a gemstone unless polished for decorative use.

Geological facts

Iron oxides produce the characteristic red, orange, brown, and sometimes silvery-black coloration. A streak test, acid test, and hand-lens examination can distinguish it from metallic ore or slag.

Field identification & locations

Look for visible sand grains, bedding, earthy red-brown coatings, and a reddish-yellow to brown streak; it should not fizz in dilute hydrochloric acid. Common in weathered continental and shallow-marine sandstone formations worldwide.