metamorphic
Tiger Iron / Banded Iron Formation
Banded Iron Formation (SiO2 with Fe2O3 and FeOOH)
Hardness: 7 (Mohs); Color: Golden-brown, metallic grey, and red bands; Luster: Silky to sub-metallic; Crystal Structure: Trigonal (as quartz/hematite microcrystals); Cleavage: None; Specific Gravity: 2.6 - 3.4
- Hardness
- 7 (Mohs)
- Color
- Golden-brown, metallic grey, and red bands
- Luster
- Silky to sub-metallic
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Physical properties
Hardness: 7 (Mohs); Color: Golden-brown, metallic grey, and red bands; Luster: Silky to sub-metallic; Crystal Structure: Trigonal (as quartz/hematite microcrystals); Cleavage: None; Specific Gravity: 2.6 - 3.4
Formation & geological history
Formed approximately 1.8 to 2.5 billion years ago in Precambrian sedimentary basins. It is a metamorphosis of tiger's eye, red jasper, and hematite layers through tectonic pressure and heat.
Uses & applications
Primarily used for ornamental carvings, jewelry (cabochons), and as a high-quality decorative stone in interior design. Also historically a minor ore of iron.
Geological facts
This specimen is essentially a mixture of three distinct minerals: Golden Tiger's Eye, Red Jasper, and Hematite. It is mostly found in the Hamersley Ranges of Western Australia.
Field identification & locations
Identify by its distinct alternating layers of yellow/gold (chatoyant), deep red, and dark metallic grey. It is heavy for its size due to the iron content. Found primarily in Australia and South Africa.
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