Demantoid Garnet
The green variety of andradite garnet, prized for its exceptional brilliance and fire. "Horsetail" inclusions (chrysotile fibers radiating from a chromite crystal) are diagnostic for Russian (Ural) demantoid but absent in Namibian material. Horsetails confirm andradite species but not the demantoid variety — color and RI confirmation are still required.
Physical & Optical Properties
Related: Garnet Varieties
Key Differentiators
- Dispersion higher than diamond
- Horsetail inclusions
- Adamantine luster
Common Simulants
- Tsavorite Garnet: Tsavorite RI ~1.740 vs demantoid 1.888; demantoid has higher dispersion (fire) and characteristic horsetail inclusions.
- Peridot: Peridot is biaxial positive DR; characteristic doubling visible under loupe; RI 1.654–1.690; SG 3.34.
- Green zircon: Zircon shows strong doubling under loupe; very high SG (4.67); birefringence visible.
- Glass: Isotropic; gas bubbles or swirl marks under loupe; conchoidal fracture; SG much lower than demantoid (3.84).
Commonly Confused With
Commonly confused with: Tsavorite Garnet, Peridot, Zircon, glass.
Treatments
- Heat Treatment (~800°F — undetectable)
Price Context
Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.
About Demantoid Garnet
The green variety of andradite garnet, prized for its exceptional brilliance and fire. "Horsetail" inclusions (chrysotile fibers radiating from a chromite crystal) are diagnostic for Russian (Ural) demantoid but absent in Namibian material. Horsetails confirm andradite species but not the demantoid variety — color and RI confirmation are still required.
Identifying a demantoid garnet? GemID walks through these tests in order — RI, SG, fluorescence, and more.
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