Banded Iron Formation

Tiger Iron

The Banded Triad

Golden Tiger Eye Bands
Metallic Silver Hematite
Deep Red Jasper

Quick Facts

FormulaSiOβ‚‚ + Feβ‚‚O₃ (banded composite)
SystemTrigonal (microcrystalline)
LusterSilky to Metallic
StreakVariable (yellow-brown to red)
TransparencyOpaque
Sp. Gravity3.0-3.5
Mohs Hardness
7

Formation & Origin

Tiger iron is a stunning combination of three minerals banded together: tiger eye (gold, silky), hematite (silver-metallic), and red jasper. It formed as part of the banded iron formations (BIFs) that were deposited on ancient ocean floors approximately 2.2-2.5 billion years ago.

During the Great Oxidation Event, photosynthetic cyanobacteria began producing oxygen, which reacted with dissolved iron in the oceans. This caused iron oxides to precipitate in alternating layers with silica-rich sediment on the seafloor. Over geological time, metamorphism transformed these layers: some iron-rich bands became hematite, some silica bands became red jasper (colored by iron), and others developed the chatoyant fibrous structure of tiger eye through the pseudomorphic replacement of crocidolite asbestos.

Every piece of tiger iron is a direct record of one of Earth's most transformative events: the moment our atmosphere gained oxygen.

Identification Guide

Tiger iron is identified by its distinct banding of three different materials: golden-brown chatoyant tiger eye, metallic-gray hematite, and deep red jasper. The banding is typically bold and clearly defined. The tiger eye bands show chatoyancy (cat's-eye shimmer) when light plays across them.

Distinguish from plain tiger eye (lacks the hematite and jasper bands), iron tiger eye (may have just two components), and banded ironstone (lacks the tiger eye chatoyancy).

Spotting Fakes

Tiger iron is not commonly faked due to its relative abundance and moderate price. The combination of chatoyant tiger eye with metallic hematite and red jasper is difficult to replicate. Be cautious of pieces where the 'hematite' bands are actually painted or where the chatoyancy is weak, indicating lower quality. The best specimens show bold, contrasting bands with strong tiger eye chatoyancy.

Cultural & Metaphysical Traditions

Presented as cultural traditions, not scientific evidence

Tiger iron is considered a powerful grounding and strength stone that combines the properties of its three components. The tiger eye provides confidence and willpower, hematite offers protection and grounding, and red jasper adds vitality and endurance. Crystal practitioners often recommend it for physical stamina and emotional resilience.

Where It's Found

Australia - Pilbara region, Western Australia

Primary source, 2.5 billion year old banded iron formation

South Africa - Northern Cape Province

Classic African specimens

Brazil - Minas Gerais

Some banded iron formation material

Price Guide

Entry$5-15 tumbled
Mid-Range$20-80 polished slabs
Collector$50-300 large display specimens

Good to Know

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Scratch test: At hardness 7, Tiger Iron can scratch glass and steel. It's durable enough for any type of jewelry.

🌍

Sources: Found in 3 notable locations worldwide, from Australia to Brazil.

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Heft test: Tiger Iron has average mineral density (3.0-3.5). It feels about as heavy as you'd expect from a stone its size.