Gemstone profile and identification guide
Andradite
Andradite is a calcium-iron garnet species that includes demantoid and melanite varieties.
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Overview
Andradite is a calcium-iron garnet species that includes demantoid and melanite varieties.
Did you know? Demantoid andradite is known for horsetail inclusions in some classic Russian material.
Use this profile as a collector reference and educational guide for quick on-page comparison, then validate with the interactive identification system.
Identification
Name: Andradite
Scientific classification: Silicate (Garnet Group: Andradite)
Hardness: 6.75 Mohs
Transparency: transparent
Lustre: vitreous to adamantine
Crystal system: Isometric (Cubic)
Primary colour: Green
Secondary colour: Brown
Colour family: Greens
High RI, cubic symmetry, and strong dispersion in transparent stones are key andradite indicators.
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: Namibia, Madagascar, Russia (Ural), Italy, Mexico
Learn more: Gem-A gemstone education resources.
Colour Variations
Andradite ranges from green (demantoid) to yellow-green, brown, and black (melanite).
Optical effects: High Dispersion
Detailed Gemology
Mineral species: Andradite
Mineral group: Garnet group
Chemical formula: Calcium iron silicate [Ca3Fe2(SiO4)3]
Mohs hardness: 6.75
Crystal system: Isometric (Cubic)
Lustre: vitreous to adamantine
Transparency: transparent
Streak: White
Cleavage: None
Fracture: Conchoidal to uneven
Specific gravity: 3.75-3.90
Refractive index: 1.880-1.889
Optical phenomena: High dispersion; horsetail inclusions in some demantoid
Colour range: Yellow green, green, brown, black
Common inclusions: Byssolite horsetails, crystals, growth zoning
Geological environment: Skarn and contact metasomatic deposits
Principal mining regions: Namibia, Madagascar, Russia (Ural), Italy, Mexico
Important commercial sources: Gem andradite, including demantoid, is sourced notably from Namibia, Madagascar, and historic Russian localities
Historical significance: Demantoid andradite became highly valued in late 19th-century jewellery.
Common treatments: Generally untreated.
Synthetic or imitation forms: Glass and synthetic garnet-like imitations exist.
Common look-alikes: Tsavorite, peridot, green zircon
Jewellery uses: Used in faceted collector stones, especially demantoid, and in collector mineral suites.
Care recommendations: Reasonably durable but protect from hard impact and abrasion in high-exposure settings.
Cross-check profile data with GIA Gem Encyclopedia and Mindat entry for Andradite.
Formation
Forms in skarns and contact-metasomatic environments associated with calcium-rich host rocks.
Origin
Gem andradite, including demantoid, is sourced notably from Namibia, Madagascar, and historic Russian localities
Uses
Best for: Used in faceted collector stones, especially demantoid, and in collector mineral suites.
Ideal uses: Faceted jewellery and collector gems highlighting dispersion.
Care
Reasonably durable but protect from hard impact and abrasion in high-exposure settings.
Need another candidate? Use advanced gemstone search or return to the identification guide.
Related gemstones by colour
Related gemstones by hardness
Commonly confused gemstones
Andradite FAQ
How can I identify Andradite?
Compare hardness (6.75 Mohs), crystal system (Isometric (Cubic)), colour profile, and lustre (vitreous to adamantine) with your sample. Then cross-check related gemstones listed above.
What colour range does Andradite appear in?
Andradite ranges from green (demantoid) to yellow-green, brown, and black (melanite).
Where is Andradite commonly used?
Faceted jewellery and collector gems highlighting dispersion.. 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.