sedimentary

Iron-rich sandstone or ironstone fragments

Ferruginous sandstone; chiefly quartz (SiO₂) cemented or stained by iron oxides such as hematite (Fe₂O₃) and goethite (FeO(OH))

AI-generated identification · may be incorrect

Typically reddish-brown to dark gray, earthy to dull luster, granular texture, and irregular fracture; hardness about 5–7 depending on quartz content, with no prominent cleavage. The dark areas may be hematite-rich cement or weathering zones.

Identified August 20, 2026More sedimentary →

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At a glance

Common name: Iron-rich sandstone or ironstone fragments
Scientific name: Ferruginous sandstone; chiefly quartz (SiO₂) cemented or stained by iron oxides such as hematite (Fe₂O₃) and goethite (FeO(OH))
Category: sedimentary
Identified: August 20, 2026
Method: Standard

AI Estimated Value

Usually $1–$10 for loose common fragments; distinctive, unusually rich, or locality-labeled specimens may sell for about $10–$40.

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-sized quartz grains were deposited and lithified, then cemented or stained by oxidized iron-bearing fluids; commonly Paleozoic to Mesozoic, though age varies by locality. The pieces appear naturally fractured rather than crystalline.

Uses & applications

Used locally as building stone, aggregate, or iron ore when sufficiently iron-rich; attractive pieces may be collected, but they are generally not jewelry-grade.

Geological facts

The red coloration (“rust”) reflects oxidized iron minerals, while gray-black zones may indicate hematite, magnetite, or reduced mineralization. A streak test can distinguish them: hematite commonly leaves a reddish-brown streak.

Field identification & locations

Look for visible sand grains, hardness near or above steel, and a red-brown streak; a magnet may detect magnetite but not ordinary hematite. Common in iron-bearing sedimentary formations worldwide, including the United States, Australia, India, and Brazil.