Green Tourmaline
Iron-bearing green tourmaline (verdelite) ranges from pale mint to deep forest green; Fe²⁺/Fe³⁺ is the primary chromophore distinguishing it from chromium-colored chrome tourmaline. Strong dichroism makes cut orientation critical for achieving the best color face-up.
Physical & Optical Properties
Related: Tourmaline Varieties
Key Differentiators
- Much lower RI (1.624-1.644) than green sapphire (1.762) or tsavorite (1.740)
- Strong dichroism — dark green vs yellowish-green; cut orientation critical
- Chelsea filter inert (Fe-colored) vs Chelsea red for chrome tourmaline
- Characteristic growth tubes parallel to c-axis visible under loupe
- Fe absorption bands at 496nm and 611nm on spectroscope
Common Simulants
- Chrome Diopside: Monoclinic DR, different RI range 1.664–1.730, birefringence 0.030; strong Cr spectrum
- Peridot: Orthorhombic DR, RI 1.654–1.690, birefringence 0.036; extreme facet doubling visible under loupe
- Green Sapphire: Corundum RI 1.762–1.778, SG 4.00; much higher density and RI
- Demantoid Garnet: Isotropic (SR), RI 1.880–1.888, SG 3.84; horsetail inclusions; much higher dispersion
- Tsavorite Garnet: Isotropic (SR), RI 1.739–1.744, SG 3.61; Chelsea red reaction; no dichroism
- Green Glass: Isotropic, gas bubbles, swirl marks, no natural inclusions; RI variable
Commonly Confused With
Commonly confused with: Prasiolite.
Treatments
- Heat Treatment
- Irradiation
- Surface Coating
Price Context
Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.
About Green Tourmaline
Iron-bearing green tourmaline (verdelite) ranges from pale mint to deep forest green; Fe²⁺/Fe³⁺ is the primary chromophore distinguishing it from chromium-colored chrome tourmaline. Strong dichroism makes cut orientation critical for achieving the best color face-up.
Identifying a green tourmaline? GemID walks through these tests in order — RI, SG, fluorescence, and more.
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