Tiger's Eye
Variety of quartz
Uncommon · SiO₂
Quartz grown together with fibres of crocidolite, the blue asbestos form of riebeckite, which later altered to golden brown iron oxides. Long described as quartz replacing the fibres, it is now read as a vein that cracked and resealed again and again, quartz and fibres growing side by side. Its chatoyancy comes from light reflected off the parallel fibres.
Identity
- Formula
- SiO₂
- Chemical class
- Silicate
- Mineral group
- Agate, Amethyst, Bloodstone, Carnelian, Chalcedony, Citrine, Jasper, Moss Agate, Onyx, Quartz, Rose Quartz, Smoky Quartz
- Also known as
- Tiger eye, Crocidolite pseudomorph
Crystallography
- Crystal system
- Trigonal
- Habits
- Fibrous, Massive
- Fracture
- Fibrous
Physical properties
- Mohs hardness
- 7
- Density
- 2.61 g/cm³
- Luster
- Silky, Vitreous
- Colors
- brown, yellow, orange, reddish brown
- Streak
- white
- Transparency
- Opaque
Geology
- Origins
- Metamorphic
- Host rocks
- Sandstone, shale and clay
- Associated minerals
- riebeckite, Quartz, Hematite, Magnetite
- Found in
- Banded iron formation deposit
- Geography
- South Africa, Australia
Classification
- Rarity
- Uncommon
- Gem quality
- Yes
Sources
- Tiger's Eye. Mindat.org (Hudson Institute of Mineralogy).
- Tiger's Eye. Gemdat.org (Hudson Institute of Mineralogy).
- P. J. Heaney, D. M. Fisher, New interpretation of the origin of tiger's-eye. Geology, 31 (4), 323-326, Geological Society of America, 2003.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Riebeckite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Quartz. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Œil-de-tigre. Wikipédia, l'encyclopédie libre (fr).
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