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

Andradite Garnet

Andradite is a fairly abundant, although less-known, member of the ugrandite garnet species, which also includes uvarovite and grossularite. Andradite makes spectacular gems that display greater color dispersion than diamond.

Colors

Yellow, Greenish Yellow, Brown, Black

  • Andradite-garnet classification

    CommonName
    Andradite Garnet
    Species
    Andradite
    Variety
    Colors
    Yellow, Greenish Yellow, Brown, Black
    AlternateNames
    Topazilite, Melanite, Demantoid
    GemstoneGroups
    Garnet
    KeySeparations
    OTL RI, lack of doubling, spectra
    ClassificationComments
    Topazilite is the translucent to transparent variety that is yellow, yellow-green or yellow-brown in color. Melanite is the opaque black variety that is subadamantine to vitreous luster. Demantoid: green to yellowish green and brownish green variety.
  • Andradite-garnet chemistry & crystallography

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

    Transparency
    Transparent - Opaque
    Dispersion
    Strength: strong fire Value: 0.057
    OpticalComments
    RefractiveIndex
    Over the Limit 1.888-1.94
    Birefringence
    OpticCharacter
    NA
    OpticSign
    NA
    PolariscopeReaction
    Singly Refractive (SR) With ADR
    Fluorescence
    SWUV: Inert
    LWUV: Inert
    CCFReaction
    Pleochroism
    None
  • Andradite-garnet characteristic physical properties

    Hardness
    6.5-7
    CharacteristicComments
    Streak
    SpecificGravity
    3.81-3.87 Typical:3.84
    Toughness
    Poor
    Inclusions
    Andradite garnet is a type II clarity stone. Due to low mohs hardness stones might show surface abrasions or scratches.
    Luster
    SubAdamantine
    Stability
    Good
    Fracture
    Conchoidal, Uneven
    Cleavage
    None