Gadolinium Gallium Garnet. A synthetic gemstone used as an early diamond substitute. GGG is manufactured by the Czochralski method and can be manufactured in many colors. With its specific gravity of 7.5, it is a lot denser than a diamond while being a lot softer (6.5 – 7.5 on Mohs scale).
Gemological Information for Gadolinium Gallium Garnet (GGG)
| Color: | Colorless to Light Brown or Yellow |
| Crystal Structure: | Cubic |
| Refractive Index: | 1.970(+.060) |
| Durability: | Fair to Good |
| Hardness: | 6.5 |
| Family: | |
| Similar Stones: | GGG can be confused with: Diamond, Zircon, Strontium Titanate, Sphene, CZ & YAG. SG, Spectrum, Magnification, and Dispersion can be used to separate GGG from other similar material. |
| Treatments: | None |
| Country of Origin: | Man-Made Material |
Gadolinium Gallium Garnet (GGG) Care
| Ultrasonic Cleaning: | Safe |
| Steam Cleaning: | Safe |
| Warm Soapy Water: | Safe |
| Chemical Attack: | Not Attacked |
| Light Sensitivity: | Turns Brown Slowly with UV Light Exposure |
| Heat Sensitivity: | Not Sensitive |