sedimentary

Banded iron formation fragment (likely jasper-rich ironstone)

Banded iron formation (BIF), commonly hematite/goethite with chert or jasper; Fe₂O₃/FeO(OH) and SiO₂

AI-generated identification · may be incorrect

Brown-gold to black, earthy to submetallic luster, fine-grained and strongly layered; hardness about 5–7, no obvious cleavage, generally dense and heavy. The image suggests iron staining and silica-rich bands, though exact identification requires a fresh surface or testing.

Identified August 12, 2026More sedimentary →

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At a glance

Common name: Banded iron formation fragment (likely jasper-rich ironstone)
Scientific name: Banded iron formation (BIF), commonly hematite/goethite with chert or jasper; Fe₂O₃/FeO(OH) and SiO₂
Category: sedimentary
Identified: August 12, 2026
Method: Standard

AI Estimated Value

$5–$30 for a common rough fragment; $30–$150 for large, strongly banded or polished specimens.

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

Chemical sediment formed when dissolved iron precipitated with silica in ancient oceans, chiefly during the Precambrian roughly 2.5–1.8 billion years ago. Later alteration commonly produced hematite, goethite, and jasper.

Uses & applications

Mainly an iron ore when sufficiently rich; attractive pieces are sold as geological specimens or lapidary material, sometimes polished for display.

Geological facts

BIF deposits represent major oxygenation changes in Earth’s atmosphere and are among the world’s most important iron resources.

Field identification & locations

Look for alternating red, brown, black, and gray silica/iron bands, high density, and a reddish-brown streak; it should not fizz in dilute acid. Common in Australia, Brazil, India, South Africa, and Minnesota, USA.