Gemstone profile and identification guide
Hawk's Eye
Hawk's eye is a blue-grey chatoyant quartz variety formed by silicification of fibrous host textures.
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Overview
Hawk's eye is a blue-grey chatoyant quartz variety formed by silicification of fibrous host textures.
Did you know? Hawk's eye is often considered the blue precursor stage to tiger's eye coloration.
Use this profile as a collector reference and educational guide for quick on-page comparison, then validate with the interactive identification system.
Identification
Name: Hawk's Eye
Scientific classification: Silicate (Quartz Pseudomorph Variety)
Hardness: 7 Mohs
Transparency: opaque
Lustre: silky
Crystal system: Trigonal
Primary colour: Blue Grey
Secondary colour: Steel Blue
Colour family: Blues
Blue-grey body color with silky cat's-eye band and quartz hardness identify hawk's eye.
Verification Status
Status: verified-core-fields
Reference priority: GIA, Gem-A, Mindat, International Gem Society
Core identity, locality, and physical-property fields reviewed against standard gemological references.
Values are reported as practical gemological ranges where appropriate.
Physical Properties
Hardness category: hard
Hardness value: 7 Mohs
Chemical composition: Silicon dioxide (SiO2) replacing fibrous crocidolite structures
Crystal system: Trigonal
Common locations: South Africa, Namibia, Australia, India
Learn more: Gem-A gemstone education resources.
Colour Variations
Blue-grey chatoyant quartz with fibrous optical effect, related to tiger's eye.
Optical effects: Chatoyancy
Detailed Gemology
Mineral species: Quartz (hawk's eye variety)
Mineral group: Quartz group
Chemical formula: Silicon dioxide (SiO2) replacing fibrous crocidolite structures
Mohs hardness: 7
Crystal system: Trigonal
Lustre: silky
Transparency: opaque
Streak: White
Cleavage: None
Fracture: Conchoidal
Specific gravity: 2.64-2.71
Refractive index: 1.544-1.553
Optical phenomena: Chatoyancy
Colour range: Blue-grey to blue-black
Common inclusions: Parallel fibrous structure and iron oxide traces
Geological environment: Silica replacement zones in metamorphosed iron formations
Principal mining regions: South Africa, Namibia, Australia, India
Important commercial sources: Most commercial hawk's eye is sourced from South Africa and Namibia
Historical significance: A long-used ornamental chatoyant quartz variety.
Common treatments: Heat and dyeing can alter color in related trade materials.
Synthetic or imitation forms: Fiber-optic glass and dyed quartz imitations are common.
Common look-alikes: Blue tiger's eye variants, cat's-eye glass
Jewellery uses: Used in cabochons, beads, carvings, and decorative inlay.
Care recommendations: Durable for jewelry; avoid severe impact and maintain polish on cabochon surface.
Cross-check profile data with GIA Gem Encyclopedia and Mindat entry for Hawk's Eye.
Formation
Forms through silica replacement of fibrous precursor minerals while preserving oriented structure.
Origin
Most commercial hawk's eye is sourced from South Africa and Namibia
Uses
Best for: Used in cabochons, beads, carvings, and decorative inlay.
Ideal uses: Cabochons where chatoyant band movement is visible under directional light.
Care
Durable for jewelry; avoid severe impact and maintain polish on cabochon surface.
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Hawk's Eye FAQ
How can I identify Hawk's Eye?
Compare hardness (7 Mohs), crystal system (Trigonal), colour profile, and lustre (silky) with your sample. Then cross-check related gemstones listed above.
What colour range does Hawk's Eye appear in?
Blue-grey chatoyant quartz with fibrous optical effect, related to tiger's eye.
Where is Hawk's Eye commonly used?
Cabochons where chatoyant band movement is visible under directional light.. For maintenance, follow the care guidance in this profile.
Scientific References
GIA: general gemstone identity (reviewed) - Batch 04 factual verification pass.
Gem-A: gemological terminology and testing references (reviewed) - Batch 04 factual verification pass.
Mindat: mineral species and principal localities (reviewed) - Batch 04 factual verification pass.
International Gem Society: gem trade context and treatment overview (reviewed) - Batch 04 factual verification pass.