Rainbow Garnet Gemstone & Information | Gemopedia by JTV | Gemopedia™

Rainbow Garnet

Also called "rainbow garnet," this gray to deep brown garnet displays phenomenal iridescence. The iridescence is caused by the way grossular and andradite garnet are mixed together in this single gem, forming a crystal structure that both scatters and traps light within the gem, creating a myriad of colors.

Colors

Greenish yellow to yellowish brown with iridescent rainbow colors

  • Rainbow-garnet classification

    CommonName
    Rainbow Garnet
    Species
    Andradite
    Variety
    Iridescent Andradite
    Colors
    Greenish yellow to yellowish brown with iridescent rainbow colors
    AlternateNames
    GemstoneGroups
    Garnet
    KeySeparations
    OTL RI, SG magnification and appearance
    ClassificationComments
    Rare stones might show chatoyancy.
  • Rainbow-garnet chemistry & crystallography

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

    Transparency
    Semitranslucent - 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
  • Rainbow-garnet characteristic physical properties

    Hardness
    6.5-7
    CharacteristicComments
    Streak
    White
    SpecificGravity
    3.81-3.87 Typical:3.84
    Toughness
    Varies
    Inclusions
    Iridescent andradite garnet is type II clarity stone. Iridescence is caused by twinning planes and occurs in parallel angled bands or patchy areas.
    Luster
    SubAdamantine
    Stability
    Fracture
    Conchoidal, Uneven
    Cleavage
    None