Gadolinium Gallium Garnet

Properties

Chemical Composition: 

Gadolinium Gallium Oxide - Gd₃Ga₅O₁₂

Classification / Type: 

G.G.G. is a man made material with a garnet internal structure. The term synthetic is not used to refer to this material, since it does not have a natural counterpart.

Colors / Varieties: 

Colorless, red, blue, green.

Crystal System / Forms: 

Cubic System

Hardness: 

5.5 - 6.5

Specific Gravity: 

7.02 - 7.09

Cleavage / Fracture: 

Nil / Conchoidal fracture.

Optic Character: 

Isotropic (S.R.)

Lustre: 

Adamantine to vitreous

Refractive Index / Birefringence: 

1.970; Range: 1.920 - 2.030

Pleochroism: 

None

Dispersion: 

0.045

Magnification: 

Generally clean

U.V. Fluorescence: 

• Colorless Impregnation: Strong yellow in longwave and weak yellow in shortwave.
• Colored Impregnation (Dyeing): Varies with dopants used.

Spectrum: 

Not characteristic

Cause of Color: 

Varies with dopants used.

Treatment (Enhancement): 

-

Specific Tests & Remarks: 

Moderate see through effect

Synthesis: 

Czochralski Method

Simulants (with key separation tests): 

Y.A.G. (S.G.), Synthetic Cubic Zirconia (S.G., dispersion), Diamond (S.G., inclusions), Strontium Titanate (S.G., dispersion), Sphene (optic character, doubling, dispersion), Synthetic Rutile (optic character, dispersion, doubling), Demantoid (spectrum, inclusions, S.G.), Spessartite (spectrum, inclusions, S.G.), Malaya Garnet (spectrum, inclusions, S.G.)

Geological Occurrence: 

-

Sources: 

In a laboratory. No natural counterpart.

Cuts & Uses: 

Facetted cuts, beads, etc.