Gemstone profile and identification guide
Demantoid
Demantoid is the green gem variety of andradite garnet, prized for high dispersion and brilliance.
Profile Navigation
Overview
Demantoid is the green gem variety of andradite garnet, prized for high dispersion and brilliance.
Did you know? The name demantoid references diamond-like brilliance and fire.
Use this profile as a collector reference and educational guide for quick on-page comparison, then validate with the interactive identification system.
Identification
Name: Demantoid
Scientific classification: Silicate (Garnet Group: Andradite Variety)
Hardness: 6.75 Mohs
Transparency: transparent
Lustre: adamantine
Crystal system: Isometric (Cubic)
Primary colour: Green
Secondary colour: Yellow Green
Colour family: Greens
High RI, isotropic optics, and strong dispersion with possible horsetail inclusions are key identifiers.
Verification Status
Status: verified-core-fields
Reference priority: GIA, Gem-A, Mindat, International Gem Society
Core identity, locality, and physical-property fields reviewed against standard gemological references.
Values are reported as practical gemological ranges where appropriate.
Physical Properties
Hardness category: hard
Hardness value: 6.75 Mohs
Chemical composition: Calcium iron silicate [Ca3Fe2(SiO4)3]
Crystal system: Isometric (Cubic)
Common locations: Russia (Ural, historic), Namibia, Madagascar, Iran, Italy
Learn more: Gem-A gemstone education resources.
Colour Variations
Transparent yellow-green to deep green andradite garnet with very high dispersion.
Optical effects: High Dispersion
Detailed Gemology
Mineral species: Andradite (demantoid variety)
Mineral group: Garnet group
Chemical formula: Calcium iron silicate [Ca3Fe2(SiO4)3]
Mohs hardness: 6.75
Crystal system: Isometric (Cubic)
Lustre: adamantine
Transparency: transparent
Streak: White
Cleavage: None
Fracture: Conchoidal to uneven
Specific gravity: 3.80-3.90
Refractive index: 1.880-1.889
Optical phenomena: High dispersion; horsetail inclusions in some stones
Colour range: Yellow green to deep green
Common inclusions: Byssolite horsetails, crystals, fingerprints
Geological environment: Skarns and serpentinized host systems
Principal mining regions: Russia (Ural, historic), Namibia, Madagascar, Iran, Italy
Important commercial sources: Current demantoid supply is largely from Namibia and Madagascar, with classic historic material from Russia
Historical significance: A celebrated garnet in late imperial Russian jewellery and modern collector trade.
Common treatments: Generally untreated.
Synthetic or imitation forms: Glass and synthetic green stones are used as simulants.
Common look-alikes: Tsavorite, peridot, green zircon
Jewellery uses: Used in high-end faceted jewellery and collector gems.
Care recommendations: Good for jewellery but protect from hard knocks and abrasion in high-wear settings.
Cross-check profile data with GIA Gem Encyclopedia and Mindat entry for Demantoid.
Formation
Forms in skarn and serpentinite-related metamorphic environments.
Origin
Current demantoid supply is largely from Namibia and Madagascar, with classic historic material from Russia
Uses
Best for: Used in high-end faceted jewellery and collector gems.
Ideal uses: Fine faceted jewellery and collector stones showing strong fire.
Care
Good for jewellery but protect from hard knocks and abrasion in high-wear settings.
Need another candidate? Use advanced gemstone search or return to the identification guide.
Related gemstones by colour
Related gemstones by hardness
Gemstones from the same mineral family
Commonly confused gemstones
Demantoid FAQ
How can I identify Demantoid?
Compare hardness (6.75 Mohs), crystal system (Isometric (Cubic)), colour profile, and lustre (adamantine) with your sample. Then cross-check related gemstones listed above.
What colour range does Demantoid appear in?
Transparent yellow-green to deep green andradite garnet with very high dispersion.
Where is Demantoid commonly used?
Fine faceted jewellery and collector stones showing strong fire.. For maintenance, follow the care guidance in this profile.
Scientific References
GIA: general gemstone identity (reviewed) - Batch 02 factual verification pass.
Gem-A: gemological terminology and testing references (reviewed) - Batch 02 factual verification pass.
Mindat: mineral species and principal localities (reviewed) - Batch 02 factual verification pass.
International Gem Society: gem trade context and treatment overview (reviewed) - Batch 02 factual verification pass.