GGG Gemstone & Information | Gemopedia by JTV | Gemopedia™

GGG

Gadolinium gallium garnet, thankfully abbreviated to GGG, is a man-made diamond simulant that entered the market in the 1960's. Today it is rarely used as a gemstone, and is instead manufactured for optical and industrial uses. The Czochralski method of gem synthesis involves the melting of various elements in a platinum crucible. A small gem crystal (called a seed) and attached to a rod is then dipped into the melt and slowly pulled away as the crystal grows around the seed. For this reason, the Czochralski method is also known as crystal pulling. Synthetic gems have the same chemical, optical, and physical properties of their natural counterparts, but are a more cost-effective alternative to a natural gem.

Colors

Colorless, Light Brown, Yellow, Orange, Blue, Green, Lilac, Red, Pink

  • Ggg classification

    CommonName
    GGG
    Species
    GGG
    Variety
    Colors
    Colorless, Light Brown, Yellow, Orange, Blue, Green, Lilac, Red, Pink
    AlternateNames
    Gadolinium Gallium Garnet. 3 G, Triple G, Galliant
    GemstoneGroups
    KeySeparations
    Negative reaction to diamond tester, OTL RI, lack of doubling, fluorescence, SG and pavilion flash.
    ClassificationComments
    Misnomer: synthetic diamond. GGG has a moderate see-through effect. Stones will have an orange and blue pavilion flash effect. A 6mm round stone will weigh about twice as much as same size diamond.
  • Ggg chemistry & crystallography

    ChemicalName
    ChemicalFormula
    Gd3Ga5O12
    Synthesis
    Czochralski pulled
    CrystalSystem
    Cubic
    ChemistryClassification
    Nature
    Synthetic
    Crystallinity
    Crystalline
    ChemistryComments
  • Ggg optical properties

    Transparency
    Transparent
    Dispersion
    Strength: moderate fire Value: 0.045
    OpticalComments
    RefractiveIndex
    Over the Limit 1.97-2.03
    Birefringence
    OpticCharacter
    NA
    OpticSign
    NA
    PolariscopeReaction
    Singly Refractive (SR)
    Fluorescence
    SWUV: moderate to strong pinkish orange
    LWUV: inert to moderate orange
    CCFReaction
    Pleochroism
    None
  • Ggg characteristic physical properties

    Hardness
    6.5
    CharacteristicComments
    Streak
    SpecificGravity
    6.95-7.09 Typical:7.05
    Toughness
    Varies
    Inclusions
    Generally inclusion free but might have gas bubbles.
    Luster
    SubAdamantine
    Stability
    Fracture
    Conchoidal
    Cleavage
    None