metamorphic

Iron-rich banded quartzite / jaspilite

Banded iron formation (BIF), chiefly quartz (SiO₂) and iron oxides (hematite, Fe₂O₃; magnetite, Fe₃O₄)

AI-generated identification · may be incorrect

Hardness about 6.5–7; gray to black, rusty red-orange and cream bands; vitreous to earthy luster. Dense, fine-grained, typically massive with no prominent cleavage; iron-rich portions may be weakly magnetic.

Identified September 6, 2026More metamorphic →

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At a glance

Common name: Iron-rich banded quartzite / jaspilite
Scientific name: Banded iron formation (BIF), chiefly quartz (SiO₂) and iron oxides (hematite, Fe₂O₃; magnetite, Fe₃O₄)
Category: metamorphic
Identified: September 6, 2026
Method: Standard

AI Estimated Value

About $5–$25 for a common hand specimen; $30–$100+ for large, vividly 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

Originally deposited as chemical marine sediments of silica and iron minerals, commonly during the Precambrian (about 3.8–1.8 billion years ago), then compacted, lithified, and metamorphosed. Weathering oxidizes iron minerals to produce the orange-brown surfaces.

Uses & applications

Used as iron ore when economically concentrated, crushed aggregate, and as an ornamental or lapidary stone. Attractive polished pieces are collected and occasionally made into cabochons.

Geological facts

The alternating bands record changes in ancient ocean chemistry and oxygen availability. The specimen’s strongly contrasting rusty bands and hard dark matrix are characteristic of weathered BIF or jaspilite.

Field identification & locations

Identify it by thin, irregular quartz-rich and iron-oxide-rich bands, exceptional hardness, heavy weight, and possible magnetism; streak testing or a magnet helps distinguish hematite-rich from magnetite-rich material. Common in Precambrian shield regions such as Minnesota, Michigan, Western Australia, Brazil, India, and South Africa.