Mineral (Pseudomorph)
Blue Tiger's Eye
Silicon Dioxide (SiO2) with Crocidolite inclusions
Hardness: 6.5–7 on Mohs scale; Color: Dark blue to blue-gray with silky bands; Luster: Silky/Vitreous; Crystal Structure: Trigonal (fibrous); Cleavage: None; Specific Gravity: 2.64–2.71
- Hardness
- 6
- Color
- Dark blue to blue-gray with silky bands
- Luster
- Silky/Vitreous
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Physical properties
Hardness: 6.5–7 on Mohs scale; Color: Dark blue to blue-gray with silky bands; Luster: Silky/Vitreous; Crystal Structure: Trigonal (fibrous); Cleavage: None; Specific Gravity: 2.64–2.71
Formation & geological history
Formed through the partial replacement of crocidolite (blue asbestos) fibers by quartz. Unlike gold Tiger's Eye, the iron in this variety has not oxidized, preserving the blue color. Found in Precambrian rocks.
Uses & applications
Primarily used for lapidary work, jewelry (beads, cabochons), and ornamental carvings. Also popular in metaphysical collections.
Geological facts
Also known as Falcon's Eye. It exhibits a unique optical phenomenon called chatoyancy (the 'cat's eye' effect), which is caused by light reflecting off the internal fibrous structure.
Field identification & locations
Identify by its unique silky blue chatoyancy when rotated under light. Common locations include South Africa, Western Australia, Brazil, and India. It is easily distinguished from gold Tiger's Eye by color.
More like this
Other mineral (pseudomorph) specimens
Limonite after Pyrite (Prophecy Stone)
Limonite (FeO(OH)·nH2O) replacing Pyrite (FeS2)
Mineral pseudomorph
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
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Tiger's Eye
Tiger's Eye (SiO2 with crocidolite inclusions)
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Azurite in Gossan
Azurite (Cu3(CO3)2(OH)2) in Limonite/Goethite matrix
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Limonite/Goethite Nodule
Iron Oxyhydroxide (primarily FeO(OH)·nH2O)
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Mixed Gemstone Collection
SiO2 (Quartz varieties) and Biogenic CaCO3 (Nacre)
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