metamorphic

Polished magnetite-rich rock, likely magnetite-bearing schist or ironstone

Magnetite (Fe₃O₄) in a foliated silicate matrix; exact identification requires testing

AI-generated identification · may be incorrect

Black to dark gray, metallic-to-submetallic luster, elongated and apparently polished; magnetite has Mohs hardness 5.5–6.5, black streak, and strong magnetism. Brown-orange patches may be iron-oxide weathering products such as hematite or goethite.

Identified September 10, 2026More metamorphic →

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At a glance

Common name: Polished magnetite-rich rock, likely magnetite-bearing schist or ironstone
Scientific name: Magnetite (Fe₃O₄) in a foliated silicate matrix; exact identification requires testing
Category: metamorphic
Identified: September 10, 2026
Method: Standard

AI Estimated Value

$5–$30 for a common polished specimen; $30–$100+ if unusually attractive, dense, or locality-documented.

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

Likely formed through metamorphism or iron-rich sedimentary processes, with magnetite concentrated during recrystallization; age depends on locality and may range from Precambrian to younger. The surface appears tumbled or polished, so natural texture is partly obscured.

Uses & applications

Used as an ornamental or educational specimen and occasionally as a lapidary material; magnetite is an important iron ore and pigment source, but this piece is primarily collectible.

Geological facts

A strong magnet attraction and black streak strongly support magnetite. If the material shows planar mineral alignment, it is probably magnetite schist; if massive and granular, it may be magnetite-rich ironstone.

Field identification & locations

Common in banded iron formations, metamorphic rocks, and igneous deposits worldwide, especially around Lake Superior, Sweden, Brazil, and India. Test magnetism, streak, and density; specific gravity is about 5.2.