sedimentary

Iron-rich banded iron formation fragment (likely hematite/magnetite ore)

Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and silica (SiO₂)

AI-generated identification · may be incorrect

Dark gray to silvery metallic surface with granular, uneven texture; likely high density and weak-to-strong magnetism depending on magnetite content. Hematite hardness ~5–6.5 Mohs; magnetite ~5.5–6.5; no obvious cleavage is visible.

Identified August 25, 2026More sedimentary →

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At a glance

Common name: Iron-rich banded iron formation fragment (likely hematite/magnetite ore)
Scientific name: Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and silica (SiO₂)
Category: sedimentary
Identified: August 25, 2026
Method: Standard

AI Estimated Value

About $2–$15 for a common rough fragment; $20–$100+ if strongly magnetic, unusually banded, or from a documented 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

Chemical sediment deposited in Precambrian oceans, commonly about 2.5–1.8 billion years ago, then compacted and metamorphosed. The Free State region near 27.6°S, 28.1°E is especially plausible for iron-rich rocks associated with the Transvaal Supergroup and nearby iron-ore districts.

Uses & applications

Iron ore for steelmaking when sufficiently rich; otherwise commonly collected as a geological specimen. Metallic hematite varieties may be used ornamentally, but this rough piece has little jewelry value.

Geological facts

A simple magnet test is useful: strong attraction suggests magnetite; a red-brown streak on unglazed porcelain supports hematite, while magnetite gives a black streak. Its apparent metallic sheen may also reflect weathered iron-oxide surfaces.

Field identification & locations

Likely regional and geologically plausible, though the photograph cannot confirm banding or mineral proportions. Check density, magnetism, and streak; avoid relying on color alone because weathering can make hematite look silvery.