Hawk's-Eye Quartz Gemstone & Information | Gemopedia by JTV | Gemopedia™
Hawks eye quartz is grayish blue in color due to the presence of crocidolite fibers which are intergrown with quartz producing a wavy, chatoyant shimmer. The word chatoyant comes from the French word chatoyer, meaning to shine like a cat's eyes. When the fibers of crocidolite oxidize (a form of alteration due to contact with air), they turn golden brown, producing the related quartz variety, tigers eye.
Gray To Grayish Blue, Blue Green
Hawks-eye-quartz classificationCommonNameHawk's-Eye QuartzSpeciesQuartzVarietyHawk's-Eye QuartzColorsGray To Grayish Blue, Blue GreenAlternateNamesHawk's-Eye, Falcon's-EyeGemstoneGroupsKeySeparationsAppearance, RI and SG. Magnification and fluorescence might be helpful.ClassificationCommentsHawk's-eye quartz is a form of tiger's eye where the quartz has replaced by the mineral crocidolite.
Hawks-eye-quartz chemistry & crystallographyChemicalNamesilicon dioxide (aka silica)ChemicalFormulaSiO2SynthesisCrystalSystemTrigonalChemistryClassificationSilicateNatureNaturalCrystallinityAggregateChemistryComments
Hawks-eye-quartz optical propertiesTransparencySemitranslucent - OpaqueDispersionOpticalCommentsRefractiveIndex1.544-1.553
Tolerance:very constantBirefringence0.009OpticCharacterUniaxialOpticSignPositivePolariscopeReactionAggregate (AGG)FluorescenceSWUV: Inert
Hawks-eye-quartz characteristic physical propertiesHardness7CharacteristicCommentsStreakSpecificGravity2.64-2.69 Typical:2.66ToughnessGoodInclusionsThe cat's-eye of the stone will be the same color as the body of the stone and will be easy to see. Hawk's-eye quartz has a wavy, parallel, fibrous structure and the cat's-eye will have a wavy appearance.LusterVitreousStabilityGoodFractureSplinteryCleavageNone