Paraiba Tourmaline
Last updated: April 2026
Paraiba tourmaline (elbaite) derives its neon blue-green to blue color from copper and manganese. Found in Paraíba, Brazil; Mozambique; and Nigeria — all localities accepted as 'Paraiba' if Cu-bearing. Cu content requires laboratory analysis (EDXRF or ICP-MS); standard gemological instruments cannot confirm it. Heat treatment to remove brownish Mn absorption is widely accepted.
Paraiba Tourmaline has a specific gravity of 3.06 and a refractive index of 1.624–1.644, with a Mohs hardness of 7.0–7.5. It is uniaxial −.
Physical & Optical Properties
Measured with a polariscope, a refractometer, a hydrostatic balance, a Chelsea filter, a UV torch, a loupe, a darkfield loupe and a spectroscope — step-by-step for each.
Through the refractometer
Drawn from the refractive index above, on a 1.40–1.81 scale. How to take this reading.
Related: Tourmaline Varieties
Key Differentiators
- Electric neon blue-green — unmistakable when genuine
- Copper (Cu) + manganese (Mn) bearing — requires EDXRF or ICP-MS lab test to confirm
- Chelsea filter shows green — copper (Cu²⁺) causes green transmission; unlike emerald (red) or iron tourmaline (neutral)
- Three origins: Brazil (most prized), Mozambique, Nigeria — all accepted as Paraiba if Cu-bearing
Common Simulants
- Aquamarine: Aquamarine: uniaxial negative; RI 1.577–1.583; SG 2.72; lacks neon intensity; uniaxial character distinguishable with polariscope.
- Blue-green apatite: Apatite: uniaxial negative; RI 1.634–1.638; similar neon look but birefringence only 0.002–0.006; SG 3.17–3.23; softer (5 Mohs).
- Blue-green glass: Isotropic; gas bubbles under loupe; no dichroism; conchoidal fracture; no facet doubling.
Commonly Confused With
Commonly confused with: Aquamarine, Glass.
Treatments
- Heat Treatment (removes Mn-absorption brownish/greenish modifier — very common, universally accepted)
Related Comparisons
Measurement Guides
Identifying a paraiba tourmaline? Loupewise walks through these tests in order — RI, SG, fluorescence, and more.
Try Loupewise Free →Studying for the GIA, FGA, or FEEG practical? Paraiba Tourmaline is one of the 132 species in Loupewise’s drill and exam pool — practice identifying it from its measured properties under timed exam conditions.
Practice exams →