metamorphic

Iron-rich metamorphic rock (likely banded iron formation fragment)

Banded iron formation; chiefly quartz (SiO₂) and iron oxides such as hematite (Fe₂O₃) and magnetite (Fe₃O₄)

AI-generated identification · may be incorrect

Hardness approximately 5.5–6.5; gray, brown, reddish, and metallic-black patches with earthy to submetallic luster. Likely fine-grained and massive, with possible weak iron-rich banding; magnetite-bearing pieces may be magnetic.

Identified September 12, 2026More metamorphic →

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At a glance

Common name: Iron-rich metamorphic rock (likely banded iron formation fragment)
Scientific name: Banded iron formation; chiefly quartz (SiO₂) and iron oxides such as hematite (Fe₂O₃) and magnetite (Fe₃O₄)
Category: metamorphic
Identified: September 12, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$150+ for large, strongly banded, polished, or locality-labeled 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 silica and dissolved iron precipitated from ancient marine waters, commonly during the Precambrian (about 3.8–1.8 billion years ago), then lithified and metamorphosed. The image is not detailed enough for confident species-level identification.

Uses & applications

Used as iron ore where iron-rich enough; attractive specimens are collected, polished, or used decoratively. Value is usually modest unless strongly banded, unusually magnetic, or from a notable locality.

Geological facts

Banded iron formations record oxygenation of Earth’s oceans and atmosphere. Red-brown coloration generally indicates oxidized iron minerals, while black metallic areas may indicate magnetite.

Field identification & locations

Common in Precambrian shields, including Australia, Brazil, Canada, India, South Africa, and Ukraine. Test with a magnet, inspect for alternating silica/iron bands, and check for a reddish-brown streak; an acid test should show no significant fizz.