sedimentary

Iron-rich sandstone or weathered ironstone pebble

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

AI-generated identification · may be incorrect

Typically rusty red-brown, dull to earthy, fine-grained, and rounded by transport; hardness about 5–7, with no obvious cleavage. The dark gray base may be fresher, less-oxidized material or a different lithologic layer.

Identified August 28, 2026More sedimentary →

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At a glance

Common name: Iron-rich sandstone or weathered ironstone pebble
Scientific name: Ferruginous sandstone, commonly quartz (SiO₂) cemented or stained by iron oxides such as hematite (Fe₂O₃) and goethite (FeO(OH))
Category: sedimentary
Identified: August 28, 2026
Method: Standard

AI Estimated Value

Typically $1–$10 for a common loose specimen; $10–$30 if unusually attractive, locality-specific, or display-quality.

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 was deposited and lithified, then colored or cemented by oxidized iron-bearing groundwater; commonly Mesozoic–Cenozoic, though age depends on locality. Its rounded shape indicates stream, beach, or glacial abrasion.

Uses & applications

Used locally as aggregate, building stone, or pigment source; ordinary pieces have little jewelry value, though attractive ironstone specimens may be collected.

Geological facts

The vivid red-brown color is caused mainly by hematite and goethite rather than the sand grains themselves.

Field identification & locations

Look for gritty texture, visible quartz grains, rusty streaks, and a reddish-brown streak; it is commonly found in river gravels, beaches, deserts, and iron-rich sedimentary formations. Exact identification would benefit from a fresh fracture, streak test, magnet test, and locality information.