Andradite Garnet (Cat's-Eye) Gemstone & Information | Gemopedia by JTV | Gemopedia™

Andradite Garnet (Cat's-Eye)

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.

Colors

Yellow Green To Brownish Orange

  • Andradite-garnet-cats-eye classification

    CommonName
    Andradite Garnet (Cat's-Eye)
    Species
    Andradite
    Variety
    Cat's-Eye Andradite Garnet
    Colors
    Yellow Green To Brownish Orange
    AlternateNames
    GemstoneGroups
    Garnet
    KeySeparations
    OTL RI, spectrum and SG
    ClassificationComments
  • Andradite-garnet-cats-eye chemistry & crystallography

    ChemicalName
    calcium iron silicate
    ChemicalFormula
    Ca3Fe2(SiO4)3
    Synthesis
    CrystalSystem
    Cubic
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Crystalline to Aggregate
    ChemistryComments
  • Andradite-garnet-cats-eye optical properties

    Transparency
    SemiTranslucent To Opaque
    Dispersion
    Strength: strong fire Value: 0.057
    OpticalComments
    RefractiveIndex
    1.888
    Birefringence
    OpticCharacter
    NA
    OpticSign
    NA
    PolariscopeReaction
    Singly Refractive (SR) With ADR
    Fluorescence
    SWUV: Inert
    LWUV: Inert
    CCFReaction
    Pleochroism
    None
  • Andradite-garnet-cats-eye characteristic physical properties

    Hardness
    6.5-7
    CharacteristicComments
    Streak
    SpecificGravity
    3.81-3.87 Typical: 3.84
    Toughness
    Good
    Inclusions
    Iridescent 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.
    Luster
    SubAdamantine
    Stability
    Fracture
    Conchoidal, Uneven
    Cleavage
    None