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

Demantoid Garnet

Demantoid garnet is one of the most desirable of all colored gemstones and extremely rare. A color variety of andradite garnet, the name demantoid originates from the old German word demant meaning "diamond-like," because of a luster and dispersion that yields a fire even higher than diamonds.

Colors

Light To Dark Green To Yellow-Green

  • Demantoid-garnet classification

    CommonName
    Demantoid Garnet
    Species
    Andradite
    Variety
    Demantoid
    Colors
    Light To Dark Green To Yellow-Green
    AlternateNames
    GemstoneGroups
    Garnet
    KeySeparations
    OTL RI reading, lack of doubling, magnification and spectrum.
    ClassificationComments
  • Demantoid-garnet chemistry & crystallography

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

    Transparency
    Transparent - Opaque
    Dispersion
    Strength: strong fire Value: 0.57
    OpticalComments
    RefractiveIndex
    1.888-0
    Birefringence
    OpticCharacter
    NA
    OpticSign
    NA
    PolariscopeReaction
    Singly Refractive (SR) With ADR
    Fluorescence
    SWUV: Inert
    LWUV: Inert
    CCFReaction
    Pleochroism
    None
  • Demantoid-garnet characteristic physical properties

    Hardness
    6.5-7
    CharacteristicComments
    Streak
    SpecificGravity
    3.81-3.87 Range:0.03/-0.03 Typical:3.84
    Toughness
    Poor
    Inclusions
    Demantoid garnet is a type II clarity stone. Stones might show surface abrasions. Some stones might contain fibrous chysotile asbestos or "horsetail inclusions". Namibian stones might show stress fractures.
    Luster
    SubAdamantine
    Stability
    Good
    Fracture
    Conchoidal, Uneven
    Cleavage
    None