Rare Madagascar Gems
Grandidierite, demantoid garnet, tourmaline, and other rare species from Madagascar's diverse geology.
madagascar grandidierite demantoid rare-gems
Introduction
Grandidierite
Madagascar's signature rare gem:
Discovery & Source
- First identified: 1902 in Madagascar
- Gem quality: Only recently available (2000s)
- Primary source: World's main supplier
- Rarity: Among rarer collector gems
Characteristics
- Colour: Blue-green to greenish-blue
- Pleochroism: Strong trichroic effect
- Hardness: 7-7.5 (suitable for jewellery)
- Crystal system: Orthorhombic
Market
- Collector gem with growing awareness
- Prices rising as awareness increases
- Limited supply maintains value
- Not yet mainstream market
Grandidierite Discovery
Demantoid Garnet
Fine green garnet production:
Discovery
- Found in early 2000s
- Significant find for collector market
- Adds to worldwide demantoid sources
- Competes with Russian, Namibian material
Characteristics
- Fine green colour possible
- Good dispersion ("fire")
- Horsetail inclusions in some material
- Andradite garnet variety
Horsetail Inclusions
- Chrysotile fiber inclusions
- Diagnostic for demantoid
- Adds value when present
- Not all Madagascar material has them
Tourmaline
Madagascar's diverse tourmaline:
Varieties Available
- Multiple colours produced
- Some neon blue-green (Paraiba-type copper-bearing)
- Rubellite (pink-red) varieties
- Chrome tourmaline (green)
- Indicolite (blue)
Paraiba-Type
- Copper-bearing tourmaline found
- Neon colours similar to Brazilian/African
- Smaller production than Mozambique
- Collector interest
Market
- Growing production
- Good quality available
- Competitive pricing
- Various colours for diverse market
Additional Species
| Gem | Notes |
|---|---|
| Chrysoberyl | Including some alexandrite colour-change |
| Spinel | Red and pink varieties available |
| Rhodolite garnet | Fine purple-red material |
| Spessartine garnet | Orange varieties |
| Labradorite | Spectrolite-quality available |
| Rose quartz | Star rose quartz noted |
| Sphene | High dispersion; collector interest |
| Kornerupine | Rare; some gem quality |
Colour-Change Gems
Madagascar produces several colour-change varieties:
Alexandrite
- Chrysoberyl variety
- Some fine colour-change material
- Competes with Brazilian, Sri Lankan
- Collector interest
Colour-Change Garnet
- Pyrope-spessartine varieties
- Blue-green to red/purple change
- Related to East African material
- Exceptional specimens highly valued
Collector Significance
Why Madagascar matters for collectors:
- Species diversity: Exceptional range of gem types
- Rare species: Primary source for several unusual gems
- Quality potential: Fine material in many species
- Discovery ongoing: New finds continue
- Value: Often excellent for quality received