GGG Gemstone & Information | Gemopedia by JTV | Gemopedia™
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.
Colorless, Light Brown, Yellow, Orange, Blue, Green, Lilac, Red, Pink
Ggg classificationCommonNameGGGSpeciesGGGVarietyColorsColorless, Light Brown, Yellow, Orange, Blue, Green, Lilac, Red, PinkAlternateNamesGadolinium Gallium Garnet. 3 G, Triple G, GalliantGemstoneGroupsKeySeparationsNegative reaction to diamond tester, OTL RI, lack of doubling, fluorescence, SG and pavilion flash.ClassificationCommentsMisnomer: 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 & crystallographyChemicalNameChemicalFormulaGd3Ga5O12SynthesisCzochralski pulledCrystalSystemCubicChemistryClassificationNatureSyntheticCrystallinityCrystallineChemistryComments
Ggg optical propertiesTransparencyTransparentDispersionStrength: moderate fire Value: 0.045OpticalCommentsRefractiveIndexOver the Limit 1.97-2.03BirefringenceOpticCharacterNAOpticSignNAPolariscopeReactionSingly Refractive (SR)FluorescenceSWUV: moderate to strong pinkish orange
LWUV: inert to moderate orangeCCFReactionPleochroismNone
Ggg characteristic physical propertiesHardness6.5CharacteristicCommentsStreakSpecificGravity6.95-7.09 Typical:7.05ToughnessVariesInclusionsGenerally inclusion free but might have gas bubbles.LusterSubAdamantineStabilityFractureConchoidalCleavageNone