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Paraiba Ethiopia

Spectroscopy · Gemology & Science

UV-Vis-NIR Spectroscopy of Paraíba Tourmaline

Absorption spectroscopy explains colour physically: it shows which wavelengths a stone absorbs, and therefore which it transmits to the eye.

By
Paraiba Ethiopia Editorial Team
Reviewed by
Review pending
Updated

What does the spectrum of copper-bearing tourmaline show?

Broad Cu²⁺-related absorption in the red and near-infrared, with a possible Mn³⁺-related band in the green-yellow region. Transmission in the blue-green produces the visible colour.

UV-Vis-NIR absorption — demonstration template

Demonstration data
40050060070080090010001100520 nm700 nm900 nmWavelength (nm)Absorbance (arb. units)
  • ~520 nm Mn³⁺-related region · Literature (general)
  • ~700 nm Cu²⁺-related band · Literature (general)
  • ~900 nm Cu²⁺-related band · Literature (general)
Synthetic curve generated from Gaussian functions to demonstrate layout. Band positions mark regions commonly discussed in published literature; they are not measurements of any stone.

References

  1. Study of optical absorption spectroscopy of Cu, Mn and Fe in tourmaline. Peer-reviewed mineralogical journal.Citation to be verified

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

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