Gemology · Gemology & Science
Gemology of Paraíba Tourmaline
Copper-bearing tourmaline shares the core gemological properties of other gem tourmaline. What sets it apart is its chemistry, which is why advanced testing is required.
- By
- Paraiba Ethiopia Editorial Team
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- Review pending
- Updated
What are its gemological properties?
Like other gem tourmaline it is doubly refractive and uniaxial, with distinct pleochroism and a hardness of about 7 to 7.5 on the Mohs scale.
| Property | Typical |
|---|---|
| Crystal system | Trigonal |
| Optic character | Uniaxial negative |
| Birefringence | Approximately 0.018–0.020 |
| Mohs hardness | About 7–7.5 |
| Pleochroism | Distinct to strong |
References
- Reference text on tourmaline-supergroup mineralogy (elbaite and related species). Academic publisher.Citation to be verified
- GIA reference on copper-bearing (Paraíba-type) tourmaline. Gemological Institute of America (GIA).Citation to be verifiedInsert a specific GIA article or Gems & Gemology paper with authors and year.
Author
Paraiba Ethiopia Editorial Team
The editorial team researches and writes Paraiba Ethiopia’s educational content on copper-bearing tourmaline, prioritising laboratory nomenclature and published gemological literature over trade claims.
Technical reviewer (assignment pending)
Independent gemological reviewer
Placeholder. A qualified gemologist will be named here once technical review of this page is complete. Until then, treat technical statements as editorially prepared but not yet independently reviewed.
First published 1 October 2026. Read our editorial policy
Continue reading
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