metamorphic

Iron-rich metamorphic rock, likely magnetite–hematite-bearing ironstone

Banded or massive iron formation (BIF), chiefly hematite (Fe₂O₃) and magnetite (Fe₃O₄), with quartz and possible iron silicates

AI-generated identification · may be incorrect

Dark reddish-brown to black, earthy-to-submetallic luster, granular texture, and irregular fracture; hardness about 5–6.5, with magnetite-bearing pieces strongly magnetic and high specific gravity (~4.5–5.3).

Identified September 9, 2026More metamorphic →

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At a glance

Common name: Iron-rich metamorphic rock, likely magnetite–hematite-bearing ironstone
Scientific name: Banded or massive iron formation (BIF), chiefly hematite (Fe₂O₃) and magnetite (Fe₃O₄), with quartz and possible iron silicates
Category: metamorphic
Identified: September 9, 2026
Method: Standard

AI Estimated Value

Typically $5–$25 for a common hand specimen; $30–$100+ for unusually banded, magnetic, or attractive polished pieces.

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 iron minerals and silica precipitated from ancient oxygen-poor oceans, later compacted, metamorphosed, and locally oxidized; many deposits are Precambrian, roughly 2.5–1.8 billion years old.

Uses & applications

Major source of iron ore for steelmaking; attractive dense specimens are collected, while polished hematite-rich material is occasionally used ornamentally.

Geological facts

The specimen’s rough, rusty appearance is consistent with iron oxidation, but an image cannot confirm whether it is BIF, hematite-rich ore, or magnetite-rich skarn.

Field identification & locations

Look for red-brown streak (hematite) or black streak and magnetism (magnetite); common in the Lake Superior region, Australia, Brazil, India, and South Africa. A streak test and magnet are useful field checks.