Andradite Garnet (Cat's-Eye) Gemstone & Information | Gemopedia by JTV | Gemopedia™
The term cat's eye, or chatoyancy, is used to describe a phenomenal optical property in gemstones, in this case andradite garnet. The effect, when present, appears as a bright, narrow slit similar to the pupils in the eyes of your favorite feline. This phenomenon is caused by parallel fibrous or needle-like inclusions that interfere with the passage of light throughout the crystal, scattering and reflecting light back to the viewer as a thin line. Andradite garnet is relatively unfamiliar to the general public, but this species includes demantoid, melanite, topazolite and schorlomite. Garnets that feature a cat's eye are a rare occurrence and should be treasured.
Yellow Green To Brownish Orange
Andradite-garnet-cats-eye classificationCommonNameAndradite Garnet (Cat's-Eye)SpeciesAndraditeVarietyCat's-Eye Andradite GarnetColorsYellow Green To Brownish OrangeAlternateNamesGemstoneGroupsGarnetKeySeparationsOTL RI, spectrum and SGClassificationComments
Andradite-garnet-cats-eye chemistry & crystallographyChemicalNamecalcium iron silicateChemicalFormulaCa3Fe2(SiO4)3SynthesisCrystalSystemCubicChemistryClassificationSilicateNatureNaturalCrystallinityCrystalline to AggregateChemistryComments
Andradite-garnet-cats-eye optical propertiesTransparencySemiTranslucent To OpaqueDispersionStrength: strong fire Value: 0.057OpticalCommentsRefractiveIndex1.888BirefringenceOpticCharacterNAOpticSignNAPolariscopeReactionSingly Refractive (SR) With ADRFluorescenceSWUV: Inert
Andradite-garnet-cats-eye characteristic physical propertiesHardness6.5-7CharacteristicCommentsStreakSpecificGravity3.81-3.87 Typical: 3.84ToughnessGoodInclusionsIridescent andradite garnet is type II clarity stone. Chatoyancy is caused by parallel needles. Due to the stones low mohs hardness it might have scratches and abrasions.LusterSubAdamantineStabilityFractureConchoidal, UnevenCleavageNone